Escape current character output

# Conflicts:
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#	extras/src/test/java/com/google/gson/typeadapters/UtcDateTypeAdapterTest.java
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#	gson/src/main/java/com/google/gson/JsonParser.java
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#	gson/src/test/java/com/google/gson/functional/TypeAdapterPrecedenceTest.java
#	gson/src/test/java/com/google/gson/internal/bind/Java17ReflectiveTypeAdapterFactoryTest.java
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#	proto/src/test/java/com/google/gson/protobuf/functional/ProtosWithPrimitiveTypesTest.java
#	shrinker-test/pom.xml
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#	shrinker-test/src/main/java/com/example/ClassWithJsonAdapterAnnotation.java
#	shrinker-test/src/main/java/com/example/ClassWithNoArgsConstructor.java
#	shrinker-test/src/main/java/com/example/ClassWithUnreferencedHasArgsConstructor.java
#	shrinker-test/src/main/java/com/example/ClassWithUnreferencedNoArgsConstructor.java
#	shrinker-test/src/main/java/com/example/ClassWithVersionAnnotations.java
#	shrinker-test/src/main/java/com/example/GenericClasses.java
#	shrinker-test/src/main/java/com/example/Main.java
#	shrinker-test/src/main/java/com/example/NoSerializedNameMain.java
#	shrinker-test/src/main/java/com/example/TestExecutor.java
#	shrinker-test/src/main/java/com/example/UnusedClass.java
#	shrinker-test/src/test/java/com/google/gson/it/ShrinkingIT.java

.git-blame-ignore-revs

@@ -0,0 +1,5 @@
+# Ignore commit which reformatted code
+2c94c757a6a9426cc2fe47bc1c63f69e7c73b7b4
+
+# Ignore commit which changed line endings consistently to LF
+c2a0e4634a2100494159add78db2ee06f5eb9be6

GsonDesignDocument.md

@@ -1,57 +1,59 @@
 # Gson Design Document
 
-This document presents issues that we faced while designing Gson. It is meant for advanced users or developers working on Gson. If you are interested in learning how to use Gson, see its user guide. 
+This document presents issues that we faced while designing Gson. It is meant for advanced users or developers working on Gson. If you are interested in learning how to use Gson, see its user guide.
 
-**Navigating the Json tree or the target Type Tree while deserializing**
+Some information in this document is outdated and does not reflect the current state of Gson. This information can however still be relevant for understanding the history of Gson.
 
-When you are deserializing a Json string into an object of desired type, you can either navigate the tree of the input, or the type tree of the desired type. Gson uses the latter approach of navigating the type of the target object. This keeps you in tight control of instantiating only the type of objects that you are expecting (essentially validating the input against the expected "schema"). By doing this, you also ignore any extra fields that the Json input has but were not expected. 
+## Navigating the Json tree or the target Type Tree while deserializing
 
-As part of Gson, we wrote a general purpose ObjectNavigator that can take any object and navigate through its fields calling a visitor of your choice. 
+When you are deserializing a Json string into an object of desired type, you can either navigate the tree of the input, or the type tree of the desired type. Gson uses the latter approach of navigating the type of the target object. This keeps you in tight control of instantiating only the type of objects that you are expecting (essentially validating the input against the expected "schema"). By doing this, you also ignore any extra fields that the Json input has but were not expected.
 
-**Supporting richer serialization semantics than deserialization semantics**
+As part of Gson, we wrote a general purpose ObjectNavigator that can take any object and navigate through its fields calling a visitor of your choice.
 
-Gson supports serialization of arbitrary collections, but can only deserialize genericized collections. this means that Gson can, in some cases, fail to deserialize Json that it wrote. This is primarily a limitation of the Java type system since when you encounter a Json array of arbitrary types there is no way to detect the types of individual elements. We could have chosen to restrict the serialization to support only generic collections, but chose not to.This is because often the user of the library are concerned with either serialization or deserialization, but not both. In such cases, there is no need to artificially restrict the serialization capabilities. 
+## Supporting richer serialization semantics than deserialization semantics
 
-**Supporting serialization and deserialization of classes that are not under your control and hence can not be modified**
+Gson supports serialization of arbitrary collections, but can only deserialize genericized collections. this means that Gson can, in some cases, fail to deserialize Json that it wrote. This is primarily a limitation of the Java type system since when you encounter a Json array of arbitrary types there is no way to detect the types of individual elements. We could have chosen to restrict the serialization to support only generic collections, but chose not to. This is because often the user of the library are concerned with either serialization or deserialization, but not both. In such cases, there is no need to artificially restrict the serialization capabilities.
 
-Some Json libraries use annotations on fields or methods to indicate which fields should be used for Json serialization. That approach essentially precludes the use of classes from JDK or third-party libraries. We solved this problem by defining the notion of Custom serializers and deserializers. This approach is not new, and was used by the JAX-RPC technology to solve essentially the same problem. 
+## Supporting serialization and deserialization of classes that are not under your control and hence can not be modified
 
-**Using Checked vs Unchecked exceptions to indicate a parsing error**
+Some Json libraries use annotations on fields or methods to indicate which fields should be used for Json serialization. That approach essentially precludes the use of classes from JDK or third-party libraries. We solved this problem by defining the notion of custom serializers and deserializers. This approach is not new, and was used by the JAX-RPC technology to solve essentially the same problem.
 
-We chose to use unchecked exceptions to indicate a parsing failure. This is primarily done because usually the client can not recover from bad input, and hence forcing them to catch a checked exception results in sloppy code in the catch() block. 
+## Using Checked vs Unchecked exceptions to indicate a parsing error
 
-**Creating class instances for deserialization**
+We chose to use unchecked exceptions to indicate a parsing failure. This is primarily done because usually the client can not recover from bad input, and hence forcing them to catch a checked exception results in sloppy code in the `catch()` block.
 
-Gson needs to create a dummy class instance before it can deserialize Json data into its fields. We could have used Guice to get such an instance, but that would have resulted in a dependency on Guice. Moreover, it probably would have done the wrong thing since Guice is expected to return a valid instance, whereas we need to create a dummy one. Worse, Gson would overwrite the fields of that instance with the incoming data there by modifying the instance for all subsequent Guice injections. This is clearly not a desired behavior. Hence, we create class instances by invoking the parameterless constructor. We also handle the primitive types, enums, collections, sets, maps and trees as a special case. 
+## Creating class instances for deserialization
 
-To solve the problem of supporting unmodifiable types, we use custom instance creators. So, if you want to use a library types that does not define a default constructor (for example, Money class), then you can register an instance creator that returns a dummy instance when asked.
+Gson needs to create a dummy class instance before it can deserialize Json data into its fields. We could have used Guice to get such an instance, but that would have resulted in a dependency on Guice. Moreover, it probably would have done the wrong thing since Guice is expected to return a valid instance, whereas we need to create a dummy one. Worse, Gson would overwrite the fields of that instance with the incoming data thereby modifying the instance for all subsequent Guice injections. This is clearly not a desired behavior. Hence, we create class instances by invoking the parameterless constructor. We also handle the primitive types, enums, collections, sets, maps and trees as a special case.
 
-**Using fields vs getters to indicate Json elements**
+To solve the problem of supporting unmodifiable types, we use custom instance creators. So, if you want to use a library type that does not define a default constructor (for example, `Money` class), then you can register an instance creator that returns a dummy instance when asked.
 
-Some Json libraries use the getters of a type to deduce the Json elements. We chose to use all fields (up the inheritance hierarchy) that are not transient, static, or synthetic. We did this because not all classes are written with suitably named getters. Moreover, getXXX or isXXX might be semantic rather than indicating properties. 
+## Using fields vs getters to indicate Json elements
 
-However, there are good arguments to support properties as well. We intend to enhance Gson in a latter version to support properties as an alternate mapping for indicating Json fields. For now, Gson is fields-based. 
+Some Json libraries use the getters of a type to deduce the Json elements. We chose to use all fields (up the inheritance hierarchy) that are not transient, static, or synthetic. We did this because not all classes are written with suitably named getters. Moreover, `getXXX` or `isXXX` might be semantic rather than indicating properties.
 
-**Why are most classes in Gson marked as final?**
+However, there are good arguments to support properties as well. We intend to enhance Gson in a later version to support properties as an alternate mapping for indicating Json fields. For now, Gson is fields-based.
 
-While Gson provides a fairly extensible architecture by providing pluggable serializers and deserializers, Gson classes were not specifically designed to be extensible. Providing non-final classes would have allowed a user to legitimately extend Gson classes, and then expect that behavior to work in all subsequent revisions. We chose to limit such use-cases by marking classes as final, and waiting until a good use-case emerges to allow extensibility. Marking a class final also has a minor benefit of providing additional optimization opportunities to Java compiler and virtual machine. 
+## Why are most classes in Gson marked as final?
 
-**Why are inner interfaces and classes used heavily in Gson?**
+While Gson provides a fairly extensible architecture by providing pluggable serializers and deserializers, Gson classes were not specifically designed to be extensible. Providing non-final classes would have allowed a user to legitimately extend Gson classes, and then expect that behavior to work in all subsequent revisions. We chose to limit such use-cases by marking classes as final, and waiting until a good use-case emerges to allow extensibility. Marking a class final also has a minor benefit of providing additional optimization opportunities to Java compiler and virtual machine.
 
-Gson uses inner classes substantially. Many of the public interfaces are inner interfaces too (see JsonSerializer.Context or JsonDeserializer.Context as an example). These are primarily done as a matter of style. For example, we could have moved JsonSerializer.Context to be a top-level class JsonSerializerContext, but chose not to do so. However, if you can give us good reasons to rename it alternately, we are open to changing this philosophy. 
+## Why are inner interfaces and classes used heavily in Gson?
 
-**Why do you provide two ways of constructing Gson?**
+Gson uses inner classes substantially. Many of the public interfaces are inner interfaces too (see `JsonSerializer.Context` or `JsonDeserializer.Context` as an example). These are primarily done as a matter of style. For example, we could have moved `JsonSerializer.Context` to be a top-level class `JsonSerializerContext`, but chose not to do so. However, if you can give us good reasons to rename it alternately, we are open to changing this philosophy.
 
-Gson can be constructed in two ways: by invoking new Gson() or by using a GsonBuilder. We chose to provide a simple no-args constructor to handle simple use-cases for Gson where you want to use default options, and quickly want to get going with writing code. For all other situations, where you need to configure Gson with options such as formatters, version controls etc, we use a builder pattern. The builder pattern allows a user to specify multiple optional settings for what essentially become constructor parameters for Gson. 
+## Why do you provide two ways of constructing Gson?
 
-**Comparing Gson with Alternate Approaches**
+Gson can be constructed in two ways: by invoking `new Gson()` or by using a `GsonBuilder`. We chose to provide a simple no-args constructor to handle simple use-cases for Gson where you want to use default options, and quickly want to get going with writing code. For all other situations, where you need to configure Gson with options such as formatters, version controls etc., we use a builder pattern. The builder pattern allows a user to specify multiple optional settings for what essentially become constructor parameters for Gson.
+
+## Comparing Gson with alternate approaches
 
 Note that these comparisons were done while developing Gson so these date back to mid to late 2007.
 
-__Comparing Gson with org.json library__
+### Comparing Gson with org.json library
 
-org.json is a much lower-level library that can be used to write a toJson() method in a class. If you can not use Gson directly (may be because of platform restrictions regarding reflection), you could use org.json to hand-code a toJson method in each object. 
+org.json is a much lower-level library that can be used to write a `toJson()` method in a class. If you can not use Gson directly (maybe because of platform restrictions regarding reflection), you could use org.json to hand-code a `toJson` method in each object.
 
-__Comparing Gson with org.json.simple library__
+### Comparing Gson with org.json.simple library
 
 org.json.simple library is very similar to org.json library and hence fairly low level. The key issue with this library is that it does not handle exceptions very well. In some cases it appeared to just eat the exception while in other cases it throws an "Error" rather than an exception.

README.md

@@ -31,7 +31,8 @@ Gson can work with arbitrary Java objects including pre-existing objects that yo
 
 There are a few open-source projects that can convert Java objects to JSON. However, most of them require that you place Java annotations in your classes; something that you can not do if you do not have access to the source-code. Most also do not fully support the use of Java Generics. Gson considers both of these as very important design goals.
 
-:information_source: Gson is currently in maintenance mode; existing bugs will be fixed, but large new features will likely not be added. If you want to add a new feature, please first search for existing GitHub issues, or create a new one to discuss the feature and get feedback.
+> [!NOTE]\
+> Gson is currently in maintenance mode; existing bugs will be fixed, but large new features will likely not be added. If you want to add a new feature, please first search for existing GitHub issues, or create a new one to discuss the feature and get feedback.
 
 ### Goals
   * Provide simple `toJson()` and `fromJson()` methods to convert Java objects to JSON and vice-versa
@@ -73,10 +74,10 @@ Despite supporting older Java versions, Gson also provides a JPMS module descrip
 These are the optional Java Platform Module System (JPMS) JDK modules which Gson depends on.
 This only applies when running Java 9 or newer.
 
-- `java.sql` (optional since Gson 2.8.9)  
+- `java.sql` (optional since Gson 2.8.9)\
 When this module is present, Gson provides default adapters for some SQL date and time classes.
 
-- `jdk.unsupported`, respectively class `sun.misc.Unsafe` (optional)  
+- `jdk.unsupported`, respectively class `sun.misc.Unsafe` (optional)\
 When this module is present, Gson can use the `Unsafe` class to create instances of classes without no-args constructor.
 However, care should be taken when relying on this. `Unsafe` is not available in all environments and its usage has some pitfalls,
 see [`GsonBuilder.disableJdkUnsafe()`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#disableJdkUnsafe()).
@@ -95,7 +96,7 @@ Older Gson versions may also support lower API levels, however this has not been
   * [Releases and change log](https://github.com/google/gson/releases): Latest releases and changes in these versions; for older releases see [`CHANGELOG.md`](CHANGELOG.md)
   * [Design document](GsonDesignDocument.md): This document discusses issues we faced while designing Gson. It also includes a comparison of Gson with other Java libraries that can be used for Json conversion
 
-Please use the ['gson' tag on StackOverflow](https://stackoverflow.com/questions/tagged/gson) or the [google-gson Google group](https://groups.google.com/group/google-gson) to discuss Gson or to post questions.
+Please use the ['gson' tag on StackOverflow](https://stackoverflow.com/questions/tagged/gson), [GitHub Discussions](https://github.com/google/gson/discussions) or the [google-gson Google group](https://groups.google.com/group/google-gson) to discuss Gson or to post questions.
 
 ### Related Content Created by Third Parties
   * [Gson Tutorial](https://www.studytrails.com/java/json/java-google-json-introduction/) by `StudyTrails`
@@ -109,11 +110,11 @@ Gson uses Maven to build the project:
 mvn clean verify
 ```
 
-JDK 11 or newer is required for building, JDK 17 is recommended.
+JDK 11 or newer is required for building, JDK 17 is recommended. Newer JDKs are currently not supported for building (but are supported when _using_ Gson).
 
 ### Contributing
 
-See the [contributing guide](https://github.com/google/.github/blob/master/CONTRIBUTING.md).  
+See the [contributing guide](https://github.com/google/.github/blob/master/CONTRIBUTING.md).\
 Please perform a quick search to check if there are already existing issues or pull requests related to your contribution.
 
 Keep in mind that Gson is in maintenance mode. If you want to add a new feature, please first search for existing GitHub issues, or create a new one to discuss the feature and get feedback.

ReleaseProcess.md

@@ -37,6 +37,72 @@ This section was borrowed heavily from [Doclava release process](https://code.go
 
 See [OSSRH Publish Guide](https://central.sonatype.org/publish/publish-guide/).
 
+## Testing Maven release workflow locally
+
+The following describes how to perform the steps of the release locally to verify that they work as desired.
+
+**Warning:** Be careful with this, these steps might be outdated or incomplete. Doublecheck that you are working on a copy of your local Gson Git repository and make sure you have followed all steps. To be safe you can also temporarily turn off your internet connection to avoid accidentally pushing changes to the real remote Git or Maven repository.\
+As an alternative to the steps described below you can instead [perform a dry run](https://maven.apache.org/maven-release/maven-release-plugin/usage.html#do-a-dry-run), though this might not behave identical to a real release.
+
+1. Make a copy of your local Gson Git repository and only work with that copy
+2. Make sure you are on the `main` branch
+3. Create a temp directory outside the Gson directory\
+   In the following steps this will be called `#gson-remote-temp#`; replace this with the actual absolute file path of the directory, using only forward slashes. For example under Windows `C:\my-dir` becomes `C:/my-dir`.
+4. Create the directory `#gson-remote-temp#/git-repo`
+5. In that directory run
+
+    ```sh
+    git init --bare --initial-branch=main .
+    ```
+
+6. Create the directory `#gson-remote-temp#/maven-repo`
+7. Edit the root `pom.xml` of Gson
+    1. Change the `<developerConnection>` to
+
+       ```txt
+       scm:git:file:///#gson-remote-temp#/git-repo
+       ```
+
+    2. Change the `<url>` of the `<distributionManagement>` to
+
+       ```txt
+       file:///#gson-remote-temp#/maven-repo
+       ```
+
+    3. If you don't want to use GPG, remove the `maven-gpg-plugin` entry from the 'release' profile.\
+       There is also an entry under `<pluginManagement>`; you can remove that as well.
+8. Commit the changes using Git
+9. Change the remote repository of the Git project
+
+    <!-- Uses `txt` instead of `sh` to avoid the `#` being highlighted in some way -->
+    ```txt
+    git remote set-url origin file:///#gson-remote-temp#/git-repo
+    ```
+
+10. Push the changes
+
+    ```sh
+    git push origin main
+    ```
+
+Now you can perform the steps of the release:
+
+1. ```sh
+   mvn release:clean
+   ```
+
+2. ```sh
+   mvn release:prepare
+   ```
+
+3. ```sh
+   mvn release:perform
+   ```
+
+4. Verify that `#gson-remote-temp#/git-repo` and `#gson-remote-temp#/maven-repo` contain all the desired changes
+5. Afterwards delete all Gson files under `${user.home}/.m2/repository/com/google/code/gson` which have been installed in your local Maven repository during the release.\
+   Otherwise Maven might not download the real Gson artifacts with these version numbers, once they are released.
+
 ## Running Benchmarks or Tests on Android
 
 * Download vogar

Troubleshooting.md

@@ -1,357 +1,389 @@
-# Troubleshooting Guide
-
-This guide describes how to troubleshoot common issues when using Gson.
-
-<!-- The '<a id="..."></a>' anchors below are used to create stable links; don't remove or rename them -->
-<!-- Use only lowercase IDs, GitHub seems to not support uppercase IDs, see also https://github.com/orgs/community/discussions/50962 -->
-
-## <a id="class-cast-exception"></a> `ClassCastException` when using deserialized object
-
-**Symptom:** `ClassCastException` is thrown when accessing an object deserialized by Gson
-
-**Reason:** Your code is most likely not type-safe
-
-**Solution:** Make sure your code adheres to the following:
-
-- Avoid raw types: Instead of calling `fromJson(..., List.class)`, create for example a `TypeToken<List<MyClass>>`.
-  See the [user guide](UserGuide.md#collections-examples) for more information.
-- When using `TypeToken` prefer the `Gson.fromJson` overloads with `TypeToken` parameter such as [`fromJson(Reader, TypeToken)`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/Gson.html#fromJson(java.io.Reader,com.google.gson.reflect.TypeToken)).
-  The overloads with `Type` parameter do not provide any type-safety guarantees.
-- When using `TypeToken` make sure you don't capture a type variable. For example avoid something like `new TypeToken<List<T>>()` (where `T` is a type variable). Due to Java [type erasure](https://dev.java/learn/generics/type-erasure/) the actual type of `T` is not available at runtime. Refactor your code to pass around `TypeToken` instances or use [`TypeToken.getParameterized(...)`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/reflect/TypeToken.html#getParameterized(java.lang.reflect.Type,java.lang.reflect.Type...)), for example `TypeToken.getParameterized(List.class, elementType)` where `elementType` is a type you have to provide separately.
-
-## <a id="reflection-inaccessible"></a> `InaccessibleObjectException`: 'module ... does not "opens ..." to unnamed module'
-
-**Symptom:** An exception with a message in the form 'module ... does not "opens ..." to unnamed module' is thrown
-
-**Reason:** You use Gson by accident to access internal fields of third-party classes
-
-**Solution:** Write custom Gson [`TypeAdapter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) implementations for the affected classes or change the type of your data. If this occurs for a field in one of your classes which you did not actually want to serialize or deserialize in the first place, you can exclude that field, see the [user guide](UserGuide.md#excluding-fields-from-serialization-and-deserialization).
-
-**Explanation:**
-
-When no built-in adapter for a type exists and no custom adapter has been registered, Gson falls back to using reflection to access the fields of a class (including `private` ones). Most likely you are seeing this error because you (by accident) rely on the reflection-based adapter for third-party classes. That should be avoided because you make yourself dependent on the implementation details of these classes which could change at any point. For the JDK it is also not possible anymore to access internal fields using reflection starting with JDK 17, see [JEP 403](https://openjdk.org/jeps/403).
-
-If you want to prevent using reflection on third-party classes in the future you can write your own [`ReflectionAccessFilter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/ReflectionAccessFilter.html) or use one of the predefined ones, such as `ReflectionAccessFilter.BLOCK_ALL_PLATFORM`.
-
-## <a id="reflection-inaccessible-to-module-gson"></a> `InaccessibleObjectException`: 'module ... does not "opens ..." to module com.google.gson'
-
-**Symptom:** An exception with a message in the form 'module ... does not "opens ..." to module com.google.gson' is thrown
-
-**Reason:**
-
-- If the reported package is your own package then you have not configured the module declaration of your project to allow Gson to use reflection on your classes.
-- If the reported package is from a third party library or the JDK see [this troubleshooting point](#inaccessibleobjectexception-module--does-not-opens--to-unnamed-module).
-
-**Solution:** Make sure the `module-info.java` file of your project allows Gson to use reflection on your classes, for example:
-
-```java
-module mymodule {
-    requires com.google.gson;
-
-    opens mypackage to com.google.gson;
-}
-```
-
-Or in case this occurs for a field in one of your classes which you did not actually want to serialize or deserialize in the first place, you can exclude that field, see the [user guide](UserGuide.md#excluding-fields-from-serialization-and-deserialization).
-
-## <a id="android-app-random-names"></a> Android app not working in Release mode; random property names
-
-**Symptom:** Your Android app is working fine in Debug mode but fails in Release mode and the JSON properties have seemingly random names such as `a`, `b`, ...
-
-**Reason:** You probably have not configured ProGuard / R8 correctly
-
-**Solution:** Make sure you have configured ProGuard / R8 correctly to preserve the names of your fields. See the [Android example](examples/android-proguard-example/README.md) for more information.
-
-## <a id="android-app-broken-after-app-update"></a> Android app unable to parse JSON after app update
-
-**Symptom:** You released a new version of your Android app and it fails to parse JSON data created by the previous version of your app
-
-**Reason:** You probably have not configured ProGuard / R8 correctly; probably the fields names are being obfuscated and their naming changed between the versions of your app
-
-**Solution:** Make sure you have configured ProGuard / R8 correctly to preserve the names of your fields. See the [Android example](examples/android-proguard-example/README.md) for more information.
-
-If you want to preserve backward compatibility for you app you can use [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html) on the fields to specify the obfuscated name as alternate, for example: `@SerializedName(value = "myprop", alternate = "a")`
-
-Normally ProGuard and R8 produce a mapping file, this makes it easier to find out the obfuscated field names instead of having to find them out through trial and error or other means. See the [Android Studio user guide](https://developer.android.com/studio/build/shrink-code.html#retracing) for more information.
-
-## <a id="default-field-values-missing"></a> Default field values not present after deserialization
-
-**Symptom:** You have assign default values to fields but after deserialization the fields have their standard value (such as `null` or `0`)
-
-**Reason:** Gson cannot invoke the constructor of your class and falls back to JDK `Unsafe` (or similar means)
-
-**Solution:** Make sure that the class:
-
-- is `static` (explicitly or implicitly when it is a top-level class)
-- has a no-args constructor
-
-Otherwise Gson will by default try to use JDK `Unsafe` or similar means to create an instance of your class without invoking the constructor and without running any initializers. You can also disable that behavior through [`GsonBuilder.disableJdkUnsafe()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#disableJdkUnsafe()) to notice such issues early on.
-
-## <a id="anonymous-local-null"></a> `null` values for anonymous and local classes
-
-**Symptom:** Objects of a class are always serialized as JSON `null` / always deserialized as Java `null`
-
-**Reason:** The class you are serializing or deserializing is an anonymous or a local class (or you have specified a custom `ExclusionStrategy`)
-
-**Solution:** Convert the class to a `static` nested class. If the class is already `static` make sure you have not specified a Gson `ExclusionStrategy` which might exclude the class.
-
-Notes:
-
-- "double brace-initialization" also creates anonymous classes
-- Local record classes (feature added in Java 16) are supported by Gson and are not affected by this
-
-## <a id="map-key-wrong-json"></a> Map keys having unexpected format in JSON
-
-**Symptom:** JSON output for `Map` keys is unexpected / cannot be deserialized again
-
-**Reason:** The `Map` key type is 'complex' and you have not configured the `GsonBuilder` properly
-
-**Solution:** Use [`GsonBuilder.enableComplexMapKeySerialization()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#enableComplexMapKeySerialization()). See also the [user guide](UserGuide.md#maps-examples) for more information.
-
-## <a id="malformed-json"></a> Parsing JSON fails with `MalformedJsonException`
-
-**Symptom:** JSON parsing fails with `MalformedJsonException`
-
-**Reason:** The JSON data is actually malformed
-
-**Solution:** During debugging, log the JSON data right before calling Gson methods or set a breakpoint to inspect the data and make sure it has the expected format. Sometimes APIs might return HTML error pages (instead of JSON data) when reaching rate limits or when other errors occur. Also read the location information of the `MalformedJsonException` exception message, it indicates where exactly in the document the malformed data was detected, including the [JSONPath](https://goessner.net/articles/JsonPath/).
-
-For example, let's assume you want to deserialize the following JSON data:
-
-```json
-{
-  "languages": [
-    "English",
-    "French",
-  ]
-}
-```
-
-This will fail with an exception similar to this one: `MalformedJsonException: Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 5 column 4 path $.languages[2]`  
-The problem here is the trailing comma (`,`) after `"French"`, trailing commas are not allowed by the JSON specification. The location information "line 5 column 4" points to the `]` in the JSON data (with some slight inaccuracies) because Gson expected another value after `,` instead of the closing `]`. The JSONPath `$.languages[2]` in the exception message also points there: `$.` refers to the root object, `languages` refers to its member of that name and `[2]` refers to the (missing) third value in the JSON array value of that member (numbering starts at 0, so it is `[2]` instead of `[3]`).  
-The proper solution here is to fix the malformed JSON data.
-
-To spot syntax errors in the JSON data easily you can open it in an editor with support for JSON, for example Visual Studio Code. It will highlight within the JSON data the error location and show why the JSON data is considered invalid.
-
-## <a id="number-parsed-as-double"></a> Integral JSON number is parsed as `double`
-
-**Symptom:** JSON data contains an integral number such as `45` but Gson returns it as `double`
-
-**Reason:** When parsing a JSON number as `Object`, Gson will by default create always return a `double`
-
-**Solution:** Use [`GsonBuilder.setObjectToNumberStrategy`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#setObjectToNumberStrategy(com.google.gson.ToNumberStrategy)) to specify what type of number should be returned
-
-## <a id="default-lenient"></a> Malformed JSON not rejected
-
-**Symptom:** Gson parses malformed JSON without throwing any exceptions
-
-**Reason:** Due to legacy reasons Gson performs parsing by default in lenient mode
-
-**Solution:** If you are using Gson 2.11.0 or newer, call [`GsonBuilder.setStrictness`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#setStrictness(com.google.gson.Strictness)),
-[`JsonReader.setStrictness`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/stream/JsonReader.html#setStrictness(com.google.gson.Strictness))
-and [`JsonWriter.setStrictness`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/stream/JsonWriter.html#setStrictness(com.google.gson.Strictness))
-with `Strictness.STRICT` to overwrite the default lenient behavior of `Gson` and make these classes strictly adhere to the JSON specification.
-Otherwise if you are using an older Gson version, see the [`Gson` class documentation](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/Gson.html#default-lenient)
-section "JSON Strictness handling" for alternative solutions.
-
-## <a id="unexpected-json-structure"></a> `IllegalStateException`: "Expected ... but was ..."
-
-**Symptom:** An `IllegalStateException` with a message in the form "Expected ... but was ..." is thrown
-
-**Reason:** The JSON data does not have the correct format
-
-**Solution:** Make sure that your classes correctly model the JSON data. Also during debugging log the JSON data right before calling Gson methods or set a breakpoint to inspect the data and make sure it has the expected format. Read the location information of the exception message, it indicates where exactly in the document the error occurred, including the [JSONPath](https://goessner.net/articles/JsonPath/).
-
-For example, let's assume you have the following Java class:
-
-```java
-class WebPage {
-    String languages;
-}
-```
-
-And you want to deserialize the following JSON data:
-
-```json
-{
-  "languages": ["English", "French"]
-}
-```
-
-This will fail with an exception similar to this one: `IllegalStateException: Expected a string but was BEGIN_ARRAY at line 2 column 17 path $.languages`  
-This means Gson expected a JSON string value but found the beginning of a JSON array (`[`). The location information "line 2 column 17" points to the `[` in the JSON data (with some slight inaccuracies), so does the JSONPath `$.languages` in the exception message. It refers to the `languages` member of the root object (`$.`).  
-The solution here is to change in the `WebPage` class the field `String languages` to `List<String> languages`.
-
-## <a id="adapter-not-null-safe"></a> `IllegalStateException`: "Expected ... but was NULL"
-
-**Symptom:** An `IllegalStateException` with a message in the form "Expected ... but was NULL" is thrown
-
-**Reason:**
-
-- A built-in adapter does not support JSON null values
-- You have written a custom `TypeAdapter` which does not properly handle JSON null values
-
-**Solution:** If this occurs for a custom adapter you wrote, add code similar to the following at the beginning of its `read` method:
-
-```java
-@Override
-public MyClass read(JsonReader in) throws IOException {
-    if (in.peek() == JsonToken.NULL) {
-        in.nextNull();
-        return null;
-    }
-
-    ...
-}
-```
-
-Alternatively you can call [`nullSafe()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html#nullSafe()) on the adapter instance you created.
-
-## <a id="serialize-nulls"></a> Properties missing in JSON
-
-**Symptom:** Properties are missing in the JSON output
-
-**Reason:** Gson by default omits JSON null from the output (or: ProGuard / R8 is not configured correctly and removed unused fields)
-
-**Solution:** Use [`GsonBuilder.serializeNulls()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#serializeNulls())
-
-Note: Gson does not support anonymous and local classes and will serialize them as JSON null, see the [related troubleshooting point](#null-values-for-anonymous-and-local-classes).
-
-## <a id="android-internal-fields"></a> JSON output changes for newer Android versions
-
-**Symptom:** The JSON output differs when running on newer Android versions
-
-**Reason:** You use Gson by accident to access internal fields of Android classes
-
-**Solution:** Write custom Gson [`TypeAdapter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) implementations for the affected classes or change the type of your data
-
-**Explanation:**
-
-When no built-in adapter for a type exists and no custom adapter has been registered, Gson falls back to using reflection to access the fields of a class (including `private` ones). Most likely you are experiencing this issue because you (by accident) rely on the reflection-based adapter for Android classes. That should be avoided because you make yourself dependent on the implementation details of these classes which could change at any point.
-
-If you want to prevent using reflection on third-party classes in the future you can write your own [`ReflectionAccessFilter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/ReflectionAccessFilter.html) or use one of the predefined ones, such as `ReflectionAccessFilter.BLOCK_ALL_PLATFORM`.
-
-## <a id="json-static-fields"></a> JSON output contains values of `static` fields
-
-**Symptom:** The JSON output contains values of `static` fields
-
-**Reason:** You used `GsonBuilder.excludeFieldsWithModifiers` to overwrite the default excluded modifiers
-
-**Solution:** When calling `GsonBuilder.excludeFieldsWithModifiers` you overwrite the default excluded modifiers. Therefore, you have to explicitly exclude `static` fields if desired. This can be done by adding `Modifier.STATIC` as additional argument.
-
-## <a id="no-such-method-error"></a> `NoSuchMethodError` when calling Gson methods
-
-**Symptom:** A `java.lang.NoSuchMethodError` is thrown when trying to call certain Gson methods
-
-**Reason:**
-
-- You have multiple versions of Gson on your classpath
-- Or, the Gson version you compiled against is different from the one on your classpath
-- Or, you are using a code shrinking tool such as ProGuard or R8 which removed methods from Gson
-
-**Solution:** First disable any code shrinking tools such as ProGuard or R8 and check if the issue persists. If not, you have to tweak the configuration of that tool to not modify Gson classes. Otherwise verify that the Gson JAR on your classpath is the same you are compiling against, and that there is only one Gson JAR on your classpath. See [this Stack Overflow question](https://stackoverflow.com/q/227486) to find out where a class is loaded from. For example, for debugging you could include the following code:
-
-```java
-System.out.println(Gson.class.getProtectionDomain().getCodeSource().getLocation());
-```
-
-If that fails with a `NullPointerException` you have to try one of the other ways to find out where a class is loaded from.
-
-## <a id="duplicate-fields"></a> `IllegalArgumentException`: 'Class ... declares multiple JSON fields named '...''
-
-**Symptom:** An exception with the message 'Class ... declares multiple JSON fields named '...'' is thrown
-
-**Reason:**
-
-- The name you have specified with a [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html) annotation for a field collides with the name of another field
-- The [`FieldNamingStrategy`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/FieldNamingStrategy.html) you have specified produces conflicting field names
-- A field of your class has the same name as the field of a superclass
-
-Gson prevents multiple fields with the same name because during deserialization it would be ambiguous for which field the JSON data should be deserialized. For serialization it would cause the same field to appear multiple times in JSON. While the JSON specification permits this, it is likely that the application parsing the JSON data will not handle it correctly.
-
-**Solution:** First identify the fields with conflicting names based on the exception message. Then decide if you want to rename one of them using the [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html) annotation, or if you want to [exclude](UserGuide.md#excluding-fields-from-serialization-and-deserialization) one of them. When excluding one of the fields you have to include it for both serialization and deserialization (even if your application only performs one of these actions) because the duplicate field check cannot differentiate between these actions.
-
-## <a id="java-lang-class-unsupported"></a> `UnsupportedOperationException` when serializing or deserializing `java.lang.Class`
-
-**Symptom:** An `UnsupportedOperationException` is thrown when trying to serialize or deserialize `java.lang.Class`
-
-**Reason:** Gson intentionally does not permit serializing and deserializing `java.lang.Class` for security reasons. Otherwise a malicious user could make your application load an arbitrary class from the classpath and, depending on what your application does with the `Class`, in the worst case perform a remote code execution attack.
-
-**Solution:** First check if you really need to serialize or deserialize a `Class`. Often it is possible to use string aliases and then map them to the known `Class`; you could write a custom [`TypeAdapter`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) to do this. If the `Class` values are not known in advance, try to introduce a common base class or interface for all these classes and then verify that the deserialized class is a subclass. For example assuming the base class is called `MyBaseClass`, your custom `TypeAdapter` should load the class like this:
-
-```java
-Class.forName(jsonString, false, getClass().getClassLoader()).asSubclass(MyBaseClass.class)
-```
-
-This will not initialize arbitrary classes, and it will throw a `ClassCastException` if the loaded class is not the same as or a subclass of `MyBaseClass`.
-
-## <a id="type-token-raw"></a> `IllegalStateException`: 'TypeToken must be created with a type argument' <br> `RuntimeException`: 'Missing type parameter'
-
-**Symptom:** An `IllegalStateException` with the message 'TypeToken must be created with a type argument' is thrown.  
-For older Gson versions a `RuntimeException` with message 'Missing type parameter' is thrown.
-
-**Reason:**
-
-- You created a `TypeToken` without type argument, for example `new TypeToken() {}` (note the missing `<...>`). You always have to provide the type argument, for example like this: `new TypeToken<List<String>>() {}`. Normally the compiler will also emit a 'raw types' warning when you forget the `<...>`.
-- You are using a code shrinking tool such as ProGuard or R8 (Android app builds normally have this enabled by default) but have not configured it correctly for usage with Gson.
-
-**Solution:** When you are using a code shrinking tool such as ProGuard or R8 you have to adjust your configuration to include the following rules:
-
-```
-# Keep generic signatures; needed for correct type resolution
--keepattributes Signature
-
-# Keep class TypeToken (respectively its generic signature)
--keep class com.google.gson.reflect.TypeToken { *; }
-
-# Keep any (anonymous) classes extending TypeToken
--keep class * extends com.google.gson.reflect.TypeToken
-```
-
-See also the [Android example](examples/android-proguard-example/README.md) for more information.
-
-Note: For newer Gson versions these rules might be applied automatically; make sure you are using the latest Gson version and the latest version of the code shrinking tool.
-
-## <a id="r8-abstract-class"></a> `JsonIOException`: 'Abstract classes can't be instantiated!' (R8)
-
-**Symptom:** A `JsonIOException` with the message 'Abstract classes can't be instantiated!' is thrown; the class mentioned in the exception message is not actually `abstract` in your source code, and you are using the code shrinking tool R8 (Android app builds normally have this configured by default).
-
-Note: If the class which you are trying to deserialize is actually abstract, then this exception is probably unrelated to R8 and you will have to implement a custom [`InstanceCreator`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/InstanceCreator.html) or [`TypeAdapter`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) which creates an instance of a non-abstract subclass of the class.
-
-**Reason:** The code shrinking tool R8 performs optimizations where it removes the no-args constructor from a class and makes the class `abstract`. Due to this Gson cannot create an instance of the class.
-
-**Solution:** Make sure the class has a no-args constructor, then adjust your R8 configuration file to keep the constructor of the class. For example:
-
-```
-# Keep the no-args constructor of the deserialized class
--keepclassmembers class com.example.MyClass {
-  <init>();
-}
-```
-
-You can also use `<init>(...);` to keep all constructors of that class, but then you might actually rely on `sun.misc.Unsafe` on both JDK and Android to create classes without no-args constructor, see [`GsonBuilder.disableJdkUnsafe()`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#disableJdkUnsafe()) for more information.
-
-For Android you can add this rule to the `proguard-rules.pro` file, see also the [Android documentation](https://developer.android.com/build/shrink-code#keep-code). In case the class name in the exception message is obfuscated, see the Android documentation about [retracing](https://developer.android.com/build/shrink-code#retracing).
-
-For Android you can alternatively use the [`@Keep` annotation](https://developer.android.com/studio/write/annotations#keep) on the class or constructor you want to keep. That might be easier than having to maintain a custom R8 configuration.
-
-Note that the latest Gson versions (> 2.10.1) specify a default R8 configuration. If your class is a top-level class or is `static`, has a no-args constructor and its fields are annotated with Gson's [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html), you might not have to perform any additional R8 configuration.
-
-## <a id="typetoken-type-variable"></a> `IllegalArgumentException`: 'TypeToken type argument must not contain a type variable'
-
-**Symptom:** An exception with the message 'TypeToken type argument must not contain a type variable' is thrown
-
-**Reason:** This exception is thrown when you create an anonymous `TypeToken` subclass which captures a type variable, for example `new TypeToken<List<T>>() {}` (where `T` is a type variable). At compile time such code looks safe and you can use the type `List<T>` without any warnings. However, this code is not actually type-safe because at runtime due to [type erasure](https://dev.java/learn/generics/type-erasure/) only the upper bound of the type variable is available. For the previous example that would be `List<Object>`. When using such a `TypeToken` with any Gson methods performing deserialization this would lead to confusing and difficult to debug `ClassCastException`s. For serialization it can in some cases also lead to undesired results.
-
-Note: Earlier version of Gson unfortunately did not prevent capturing type variables, which caused many users to unwittingly write type-unsafe code.
-
-**Solution:**
-
-- Use [`TypeToken.getParameterized(...)`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/reflect/TypeToken.html#getParameterized(java.lang.reflect.Type,java.lang.reflect.Type...)), for example `TypeToken.getParameterized(List.class, elementType)` where `elementType` is a type you have to provide separately.
-- For Kotlin users: Use [`reified` type parameters](https://kotlinlang.org/docs/inline-functions.html#reified-type-parameters), that means change `<T>` to `<reified T>`, if possible. If you have a chain of functions with type parameters you will probably have to make all of them `reified`.
-- If you don't actually use Gson's `TypeToken` for any Gson method, use a general purpose 'type token' implementation provided by a different library instead, for example Guava's [`com.google.common.reflect.TypeToken`](https://javadoc.io/doc/com.google.guava/guava/latest/com/google/common/reflect/TypeToken.html).
-
-For backward compatibility it is possible to restore Gson's old behavior of allowing `TypeToken` to capture type variables by setting the [system property](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/System.html#setProperty(java.lang.String,java.lang.String)) `gson.allowCapturingTypeVariables` to `"true"`, **however**:
-
-- This does not solve any of the type-safety problems mentioned above; in the long term you should prefer one of the other solutions listed above. This system property might be removed in future Gson versions.
-- You should only ever set the property to `"true"`, but never to any other value or manually clear it. Otherwise this might counteract any libraries you are using which might have deliberately set the system property because they rely on its behavior.
+# Troubleshooting Guide
+
+This guide describes how to troubleshoot common issues when using Gson.
+
+<!-- The '<a id="..."></a>' anchors below are used to create stable links; don't remove or rename them -->
+<!-- Use only lowercase IDs, GitHub seems to not support uppercase IDs, see also https://github.com/orgs/community/discussions/50962 -->
+
+## <a id="class-cast-exception"></a> `ClassCastException` when using deserialized object
+
+**Symptom:** `ClassCastException` is thrown when accessing an object deserialized by Gson
+
+**Reason:** Your code is most likely not type-safe
+
+**Solution:** Make sure your code adheres to the following:
+
+- Avoid raw types: Instead of calling `fromJson(..., List.class)`, create for example a `TypeToken<List<MyClass>>`.
+  See the [user guide](UserGuide.md#collections-examples) for more information.
+- When using `TypeToken` prefer the `Gson.fromJson` overloads with `TypeToken` parameter such as [`fromJson(Reader, TypeToken)`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/Gson.html#fromJson(java.io.Reader,com.google.gson.reflect.TypeToken)).
+  The overloads with `Type` parameter do not provide any type-safety guarantees.
+- When using `TypeToken` make sure you don't capture a type variable. For example avoid something like `new TypeToken<List<T>>()` (where `T` is a type variable). Due to Java [type erasure](https://dev.java/learn/generics/type-erasure/) the actual type of `T` is not available at runtime. Refactor your code to pass around `TypeToken` instances or use [`TypeToken.getParameterized(...)`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/reflect/TypeToken.html#getParameterized(java.lang.reflect.Type,java.lang.reflect.Type...)), for example `TypeToken.getParameterized(List.class, elementType)` where `elementType` is a type you have to provide separately.
+
+## <a id="reflection-inaccessible"></a> `InaccessibleObjectException`: 'module ... does not "opens ..." to unnamed module'
+
+**Symptom:** An exception with a message in the form 'module ... does not "opens ..." to unnamed module' is thrown
+
+**Reason:** You use Gson by accident to access internal fields of third-party classes
+
+**Solution:** Write custom Gson [`TypeAdapter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) implementations for the affected classes or change the type of your data.
+If you already wrote a custom adapter, but it is not used, see [this troubleshooting point](#custom-adapter-not-used).\
+If this occurs for a field in one of your classes which you did not actually want to serialize or deserialize in the first place, you can exclude that field, see the [user guide](UserGuide.md#excluding-fields-from-serialization-and-deserialization).
+
+**Explanation:**
+
+When no built-in adapter for a type exists and no custom adapter has been registered, Gson falls back to using reflection to access the fields of a class (including `private` ones). Most likely you are seeing this error because you (by accident) rely on the reflection-based adapter for third-party classes. That should be avoided because you make yourself dependent on the implementation details of these classes which could change at any point. For the JDK it is also not possible anymore to access internal fields using reflection starting with JDK 17, see [JEP 403](https://openjdk.org/jeps/403).
+
+If you want to prevent using reflection on third-party classes in the future you can write your own [`ReflectionAccessFilter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/ReflectionAccessFilter.html) or use one of the predefined ones, such as `ReflectionAccessFilter.BLOCK_ALL_PLATFORM`.
+
+## <a id="reflection-inaccessible-to-module-gson"></a> `InaccessibleObjectException`: 'module ... does not "opens ..." to module com.google.gson'
+
+**Symptom:** An exception with a message in the form 'module ... does not "opens ..." to module com.google.gson' is thrown
+
+**Reason:**
+
+- If the reported package is your own package then you have not configured the module declaration of your project to allow Gson to use reflection on your classes.
+- If the reported package is from a third party library or the JDK see [this troubleshooting point](#inaccessibleobjectexception-module--does-not-opens--to-unnamed-module).
+
+**Solution:** Make sure the `module-info.java` file of your project allows Gson to use reflection on your classes, for example:
+
+```java
+module mymodule {
+    requires com.google.gson;
+
+    opens mypackage to com.google.gson;
+}
+```
+
+Or in case this occurs for a field in one of your classes which you did not actually want to serialize or deserialize in the first place, you can exclude that field, see the [user guide](UserGuide.md#excluding-fields-from-serialization-and-deserialization).
+
+## <a id="android-app-random-names"></a> Android app not working in Release mode; random property names
+
+**Symptom:** Your Android app is working fine in Debug mode but fails in Release mode and the JSON properties have seemingly random names such as `a`, `b`, ...
+
+**Reason:** You probably have not configured ProGuard / R8 correctly
+
+**Solution:** Make sure you have configured ProGuard / R8 correctly to preserve the names of your fields. See the [Android example](examples/android-proguard-example/README.md) for more information.
+
+## <a id="android-app-broken-after-app-update"></a> Android app unable to parse JSON after app update
+
+**Symptom:** You released a new version of your Android app and it fails to parse JSON data created by the previous version of your app
+
+**Reason:** You probably have not configured ProGuard / R8 correctly; probably the field names are being obfuscated and their naming changed between the versions of your app
+
+**Solution:** Make sure you have configured ProGuard / R8 correctly to preserve the names of your fields. See the [Android example](examples/android-proguard-example/README.md) for more information.
+
+If you want to preserve backward compatibility for you app you can use [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html) on the fields to specify the obfuscated name as alternate, for example: `@SerializedName(value = "myprop", alternate = "a")`
+
+Normally ProGuard and R8 produce a mapping file, this makes it easier to find out the obfuscated field names instead of having to find them out through trial and error or other means. See the [Android Studio user guide](https://developer.android.com/studio/build/shrink-code.html#retracing) for more information.
+
+## <a id="default-field-values-missing"></a> Default field values not present after deserialization
+
+**Symptom:** You have assign default values to fields but after deserialization the fields have their standard value (such as `null` or `0`)
+
+**Reason:** Gson cannot invoke the constructor of your class and falls back to JDK `Unsafe` (or similar means)
+
+**Solution:** Make sure that the class:
+
+- is `static` (explicitly or implicitly when it is a top-level class)
+- has a no-args constructor
+
+Otherwise Gson will by default try to use JDK `Unsafe` or similar means to create an instance of your class without invoking the constructor and without running any initializers. You can also disable that behavior through [`GsonBuilder.disableJdkUnsafe()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#disableJdkUnsafe()) to notice such issues early on.
+
+## <a id="anonymous-local-null"></a> `null` values for anonymous and local classes
+
+**Symptom:** Objects of a class are always serialized as JSON `null` / always deserialized as Java `null`
+
+**Reason:** The class you are serializing or deserializing is an anonymous or a local class (or you have specified a custom `ExclusionStrategy`)
+
+**Solution:** Convert the class to a `static` nested class. If the class is already `static` make sure you have not specified a Gson `ExclusionStrategy` which might exclude the class.
+
+Notes:
+
+- "double brace-initialization" also creates anonymous classes
+- Local record classes (feature added in Java 16) are supported by Gson and are not affected by this
+
+## <a id="map-key-wrong-json"></a> Map keys having unexpected format in JSON
+
+**Symptom:** JSON output for `Map` keys is unexpected / cannot be deserialized again
+
+**Reason:** The `Map` key type is 'complex' and you have not configured the `GsonBuilder` properly
+
+**Solution:** Use [`GsonBuilder.enableComplexMapKeySerialization()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#enableComplexMapKeySerialization()). See also the [user guide](UserGuide.md#maps-examples) for more information.
+
+## <a id="malformed-json"></a> Parsing JSON fails with `MalformedJsonException`
+
+**Symptom:** JSON parsing fails with `MalformedJsonException`
+
+**Reason:** The JSON data is actually malformed
+
+**Solution:** During debugging, log the JSON data right before calling Gson methods or set a breakpoint to inspect the data and make sure it has the expected format. Sometimes APIs might return HTML error pages (instead of JSON data) when reaching rate limits or when other errors occur. Also read the location information of the `MalformedJsonException` exception message, it indicates where exactly in the document the malformed data was detected, including the [JSONPath](https://goessner.net/articles/JsonPath/).
+
+For example, let's assume you want to deserialize the following JSON data:
+
+```json
+{
+  "languages": [
+    "English",
+    "French",
+  ]
+}
+```
+
+This will fail with an exception similar to this one: `MalformedJsonException: Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 5 column 4 path $.languages[2]`\
+The problem here is the trailing comma (`,`) after `"French"`, trailing commas are not allowed by the JSON specification. The location information "line 5 column 4" points to the `]` in the JSON data (with some slight inaccuracies) because Gson expected another value after `,` instead of the closing `]`. The JSONPath `$.languages[2]` in the exception message also points there: `$.` refers to the root object, `languages` refers to its member of that name and `[2]` refers to the (missing) third value in the JSON array value of that member (numbering starts at 0, so it is `[2]` instead of `[3]`).\
+The proper solution here is to fix the malformed JSON data.
+
+To spot syntax errors in the JSON data easily you can open it in an editor with support for JSON, for example Visual Studio Code. It will highlight within the JSON data the error location and show why the JSON data is considered invalid.
+
+## <a id="number-parsed-as-double"></a> Integral JSON number is parsed as `double`
+
+**Symptom:** JSON data contains an integral number such as `45` but Gson returns it as `double`
+
+**Reason:** When parsing a JSON number as `Object`, Gson will by default always return a `double`
+
+**Solution:** Use [`GsonBuilder.setObjectToNumberStrategy`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#setObjectToNumberStrategy(com.google.gson.ToNumberStrategy)) to specify what type of number should be returned
+
+## <a id="default-lenient"></a> Malformed JSON not rejected
+
+**Symptom:** Gson parses malformed JSON without throwing any exceptions
+
+**Reason:** Due to legacy reasons Gson performs parsing by default in lenient mode
+
+**Solution:** If you are using Gson 2.11.0 or newer, call [`GsonBuilder.setStrictness`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#setStrictness(com.google.gson.Strictness)),
+[`JsonReader.setStrictness`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/stream/JsonReader.html#setStrictness(com.google.gson.Strictness))
+and [`JsonWriter.setStrictness`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/stream/JsonWriter.html#setStrictness(com.google.gson.Strictness))
+with `Strictness.STRICT` to overwrite the default lenient behavior of `Gson` and make these classes strictly adhere to the JSON specification.
+Otherwise if you are using an older Gson version, see the [`Gson` class documentation](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/Gson.html#default-lenient)
+section "JSON Strictness handling" for alternative solutions.
+
+## <a id="unexpected-json-structure"></a> `IllegalStateException`: "Expected ... but was ..."
+
+**Symptom:** An `IllegalStateException` with a message in the form "Expected ... but was ..." is thrown
+
+**Reason:**
+
+- The JSON data does not have the correct format
+- Or, Gson has no built-in adapter for a type and tries to deserialize it as JSON object
+
+**Solution:** Make sure that your classes correctly model the JSON data. Also during debugging log the JSON data right before calling Gson methods or set a breakpoint to inspect the data and make sure it has the expected format. Read the location information of the exception message, it indicates where exactly in the document the error occurred, including the [JSONPath](https://goessner.net/articles/JsonPath/).
+
+For example, let's assume you have the following Java class:
+
+```java
+class WebPage {
+    String languages;
+}
+```
+
+And you want to deserialize the following JSON data:
+
+```json
+{
+  "languages": ["English", "French"]
+}
+```
+
+This will fail with an exception similar to this one: `IllegalStateException: Expected a string but was BEGIN_ARRAY at line 2 column 17 path $.languages`\
+This means Gson expected a JSON string value but found the beginning of a JSON array (`[`). The location information "line 2 column 17" points to the `[` in the JSON data (with some slight inaccuracies), so does the JSONPath `$.languages` in the exception message. It refers to the `languages` member of the root object (`$.`).\
+The solution here is to change in the `WebPage` class the field `String languages` to `List<String> languages`.
+
+If you are sure that the JSON data is correct and the exception message is "Expected BEGIN_OBJECT but was ...", then this might indicate that Gson has no built-in adapter for the type.
+Gson then tries to use reflection and expects that the data is a JSON object (hence the error message "Expected BEGIN_OBJECT ..."). In that case you have to write a custom [`TypeAdapter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) for that type. If you already wrote a custom adapter, but it is not used, see [this troubleshooting point](#custom-adapter-not-used).
+
+## <a id="adapter-not-null-safe"></a> `IllegalStateException`: "Expected ... but was NULL"
+
+**Symptom:** An `IllegalStateException` with a message in the form "Expected ... but was NULL" is thrown
+
+**Reason:**
+
+- A built-in adapter does not support JSON null values
+- You have written a custom `TypeAdapter` which does not properly handle JSON null values
+
+**Solution:** If this occurs for a custom adapter you wrote, add code similar to the following at the beginning of its `read` method:
+
+```java
+@Override
+public MyClass read(JsonReader in) throws IOException {
+    if (in.peek() == JsonToken.NULL) {
+        in.nextNull();
+        return null;
+    }
+
+    ...
+}
+```
+
+Alternatively you can call [`nullSafe()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html#nullSafe()) on the adapter instance you created.
+
+## <a id="serialize-nulls"></a> Properties missing in JSON
+
+**Symptom:** Properties are missing in the JSON output
+
+**Reason:** Gson by default omits JSON null from the output (or: ProGuard / R8 is not configured correctly and removed unused fields)
+
+**Solution:** Use [`GsonBuilder.serializeNulls()`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#serializeNulls())
+
+Note: Gson does not support anonymous and local classes and will serialize them as JSON null, see the [related troubleshooting point](#null-values-for-anonymous-and-local-classes).
+
+## <a id="android-internal-fields"></a> JSON output changes for newer Android versions
+
+**Symptom:** The JSON output differs when running on newer Android versions
+
+**Reason:** You use Gson by accident to access internal fields of Android classes
+
+**Solution:** Write custom Gson [`TypeAdapter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) implementations for the affected classes or change the type of your data
+
+**Explanation:**
+
+When no built-in adapter for a type exists and no custom adapter has been registered, Gson falls back to using reflection to access the fields of a class (including `private` ones). Most likely you are experiencing this issue because you (by accident) rely on the reflection-based adapter for Android classes. That should be avoided because you make yourself dependent on the implementation details of these classes which could change at any point.
+
+If you want to prevent using reflection on third-party classes in the future you can write your own [`ReflectionAccessFilter`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/ReflectionAccessFilter.html) or use one of the predefined ones, such as `ReflectionAccessFilter.BLOCK_ALL_PLATFORM`.
+
+## <a id="json-static-fields"></a> JSON output contains values of `static` fields
+
+**Symptom:** The JSON output contains values of `static` fields
+
+**Reason:** You used `GsonBuilder.excludeFieldsWithModifiers` to overwrite the default excluded modifiers
+
+**Solution:** When calling `GsonBuilder.excludeFieldsWithModifiers` you overwrite the default excluded modifiers. Therefore, you have to explicitly exclude `static` fields if desired. This can be done by adding `Modifier.STATIC` as additional argument.
+
+## <a id="no-such-method-error"></a> `NoSuchMethodError` when calling Gson methods
+
+**Symptom:** A `java.lang.NoSuchMethodError` is thrown when trying to call certain Gson methods
+
+**Reason:**
+
+- You have multiple versions of Gson on your classpath
+- Or, the Gson version you compiled against is different from the one on your classpath
+- Or, you are using a code shrinking tool such as ProGuard or R8 which removed methods from Gson
+
+**Solution:** First disable any code shrinking tools such as ProGuard or R8 and check if the issue persists. If not, you have to tweak the configuration of that tool to not modify Gson classes. Otherwise verify that the Gson JAR on your classpath is the same you are compiling against, and that there is only one Gson JAR on your classpath. See [this Stack Overflow question](https://stackoverflow.com/q/227486) to find out where a class is loaded from. For example, for debugging you could include the following code:
+
+```java
+System.out.println(Gson.class.getProtectionDomain().getCodeSource().getLocation());
+```
+
+If that fails with a `NullPointerException` you have to try one of the other ways to find out where a class is loaded from.
+
+## <a id="duplicate-fields"></a> `IllegalArgumentException`: 'Class ... declares multiple JSON fields named '...''
+
+**Symptom:** An exception with the message 'Class ... declares multiple JSON fields named '...'' is thrown
+
+**Reason:**
+
+- The name you have specified with a [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html) annotation for a field collides with the name of another field
+- The [`FieldNamingStrategy`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/FieldNamingStrategy.html) you have specified produces conflicting field names
+- A field of your class has the same name as the field of a superclass
+
+Gson prevents multiple fields with the same name because during deserialization it would be ambiguous for which field the JSON data should be deserialized. For serialization it would cause the same field to appear multiple times in JSON. While the JSON specification permits this, it is likely that the application parsing the JSON data will not handle it correctly.
+
+**Solution:** First identify the fields with conflicting names based on the exception message. Then decide if you want to rename one of them using the [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html) annotation, or if you want to [exclude](UserGuide.md#excluding-fields-from-serialization-and-deserialization) one of them. When excluding one of the fields you have to include it for both serialization and deserialization (even if your application only performs one of these actions) because the duplicate field check cannot differentiate between these actions.
+
+## <a id="java-lang-class-unsupported"></a> `UnsupportedOperationException` when serializing or deserializing `java.lang.Class`
+
+**Symptom:** An `UnsupportedOperationException` is thrown when trying to serialize or deserialize `java.lang.Class`
+
+**Reason:** Gson intentionally does not permit serializing and deserializing `java.lang.Class` for security reasons. Otherwise a malicious user could make your application load an arbitrary class from the classpath and, depending on what your application does with the `Class`, in the worst case perform a remote code execution attack.
+
+**Solution:** First check if you really need to serialize or deserialize a `Class`. Often it is possible to use string aliases and then map them to the known `Class`; you could write a custom [`TypeAdapter`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) to do this. If the `Class` values are not known in advance, try to introduce a common base class or interface for all these classes and then verify that the deserialized class is a subclass. For example assuming the base class is called `MyBaseClass`, your custom `TypeAdapter` should load the class like this:
+
+```java
+Class.forName(jsonString, false, getClass().getClassLoader()).asSubclass(MyBaseClass.class)
+```
+
+This will not initialize arbitrary classes, and it will throw a `ClassCastException` if the loaded class is not the same as or a subclass of `MyBaseClass`.
+
+## <a id="custom-adapter-not-used"></a> Custom type adapter is not used
+
+**Symptom:** You have registered a custom `TypeAdapter` (or `JsonSerializer` or `JsonDeserializer`) on a `GsonBuilder`, but Gson is not using your adapter
+
+**Reason:**
+
+- You registered the adapter for the wrong type
+- Or, you are serializing or deserializing a subclass
+- Or, your custom `Gson` instance is not actually used
+
+**Solution:**
+
+- Debug your code and verify that the custom `Gson` instance on which you have registered the adapter is actually used. Possibly parts of your application are using a different `Gson` instance, or you are using a framework such as Spring which is using a different `Gson` instance with default configuration (in that case have a look at the framework-specific configuration options).
+- Verify that you are registering the adapter for the correct type. `GsonBuilder.registerTypeAdapter(...)` takes the adapter as `Object` argument, so you will not see a compilation error when you provide the wrong type.
+  For example when you want to register an adapter for `MyClass`, you should call `registerTypeAdapter(MyClass.class, new MyClassAdapter())`.\
+  Also pay close attention to the package name, there are classes with the same name in different packages, such as `java.util.Date` and `java.sql.Date`.
+- `registerTypeAdapter` only registers an adapter for the specified class, _but not for subclasses_. Use [`registerTypeHierarchyAdapter`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#registerTypeHierarchyAdapter(java.lang.Class,java.lang.Object))
+  to also handle subclasses.
+- Be careful with parameterized types for `registerTypeAdapter` because Gson only uses the adapter if there is an exact match for the types.
+  For example if you register an adapter for `List<Number>` it won't be used for `List` (raw type), `List<Integer>` or `ArrayList<Number>`.
+  You can solve this by writing a [`TypeAdapterFactory`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapterFactory.html) instead, which manually checks if the type matches.
+- If you want to register an adapter for a primitive type such as `boolean`, you might also want to register it for the wrapper type `java.lang.Boolean`, and the other way around.
+- The built-in adapters for `JsonElement` (and subclasses) and for `Object` cannot be overwritten. However, as workaround for a field of those types you can use the [`@JsonAdapter` annotation](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/JsonAdapter.html) to specify a custom adapter.
+
+## <a id="type-token-raw"></a> `IllegalStateException`: 'TypeToken must be created with a type argument' <br> `RuntimeException`: 'Missing type parameter'
+
+**Symptom:** An `IllegalStateException` with the message 'TypeToken must be created with a type argument' is thrown.\
+For older Gson versions a `RuntimeException` with message 'Missing type parameter' is thrown.
+
+**Reason:**
+
+- You created a `TypeToken` without type argument, for example `new TypeToken() {}` (note the missing `<...>`). You always have to provide the type argument, for example like this: `new TypeToken<List<String>>() {}`. Normally the compiler will also emit a 'raw types' warning when you forget the `<...>`.
+- You are using a code shrinking tool such as ProGuard or R8 (Android app builds normally have this enabled by default) but have not configured it correctly for usage with Gson.
+
+**Solution:** When you are using a code shrinking tool such as ProGuard or R8 you have to adjust your configuration to include the following rules:
+
+```
+# Keep generic signatures; needed for correct type resolution
+-keepattributes Signature
+
+# Keep class TypeToken (respectively its generic signature)
+-keep class com.google.gson.reflect.TypeToken { *; }
+
+# Keep any (anonymous) classes extending TypeToken
+-keep class * extends com.google.gson.reflect.TypeToken
+```
+
+See also the [Android example](examples/android-proguard-example/README.md) for more information.
+
+Note: For newer Gson versions these rules might be applied automatically; make sure you are using the latest Gson version and the latest version of the code shrinking tool.
+
+## <a id="r8-abstract-class"></a> `JsonIOException`: 'Abstract classes can't be instantiated!' (R8)
+
+**Symptom:** A `JsonIOException` with the message 'Abstract classes can't be instantiated!' is thrown; the class mentioned in the exception message is not actually `abstract` in your source code, and you are using the code shrinking tool R8 (Android app builds normally have this configured by default).
+
+Note: If the class which you are trying to deserialize is actually abstract, then this exception is probably unrelated to R8 and you will have to implement a custom [`InstanceCreator`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/InstanceCreator.html) or [`TypeAdapter`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) which creates an instance of a non-abstract subclass of the class. If you already wrote a custom adapter, but it is not used, see [this troubleshooting point](#custom-adapter-not-used).
+
+**Reason:** The code shrinking tool R8 performs optimizations where it removes the no-args constructor from a class and makes the class `abstract`. Due to this Gson cannot create an instance of the class.
+
+**Solution:** Make sure the class has a no-args constructor, then adjust your R8 configuration file to keep the constructor of the class. For example:
+
+```
+# Keep the no-args constructor of the deserialized class
+-keepclassmembers class com.example.MyClass {
+  <init>();
+}
+```
+
+You can also use `<init>(...);` to keep all constructors of that class, but then you might actually rely on `sun.misc.Unsafe` on both JDK and Android to create classes without no-args constructor, see [`GsonBuilder.disableJdkUnsafe()`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#disableJdkUnsafe()) for more information.
+
+For Android you can add this rule to the `proguard-rules.pro` file, see also the [Android documentation](https://developer.android.com/build/shrink-code#keep-code). In case the class name in the exception message is obfuscated, see the Android documentation about [retracing](https://developer.android.com/build/shrink-code#retracing).
+
+For Android you can alternatively use the [`@Keep` annotation](https://developer.android.com/studio/write/annotations#keep) on the class or constructor you want to keep. That might be easier than having to maintain a custom R8 configuration.
+
+Note that the latest Gson versions (> 2.10.1) specify a default R8 configuration. If your class is a top-level class or is `static`, has a no-args constructor and its fields are annotated with Gson's [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html), you might not have to perform any additional R8 configuration.
+
+## <a id="typetoken-type-variable"></a> `IllegalArgumentException`: 'TypeToken type argument must not contain a type variable'
+
+**Symptom:** An exception with the message 'TypeToken type argument must not contain a type variable' is thrown
+
+**Reason:** This exception is thrown when you create an anonymous `TypeToken` subclass which captures a type variable, for example `new TypeToken<List<T>>() {}` (where `T` is a type variable). At compile time such code looks safe and you can use the type `List<T>` without any warnings. However, this code is not actually type-safe because at runtime due to [type erasure](https://dev.java/learn/generics/type-erasure/) only the upper bound of the type variable is available. For the previous example that would be `List<Object>`. When using such a `TypeToken` with any Gson methods performing deserialization this would lead to confusing and difficult to debug `ClassCastException`s. For serialization it can in some cases also lead to undesired results.
+
+Note: Earlier version of Gson unfortunately did not prevent capturing type variables, which caused many users to unwittingly write type-unsafe code.
+
+**Solution:**
+
+- Use [`TypeToken.getParameterized(...)`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/reflect/TypeToken.html#getParameterized(java.lang.reflect.Type,java.lang.reflect.Type...)), for example `TypeToken.getParameterized(List.class, elementType)` where `elementType` is a type you have to provide separately.
+- For Kotlin users: Use [`reified` type parameters](https://kotlinlang.org/docs/inline-functions.html#reified-type-parameters), that means change `<T>` to `<reified T>`, if possible. If you have a chain of functions with type parameters you will probably have to make all of them `reified`.
+- If you don't actually use Gson's `TypeToken` for any Gson method, use a general purpose 'type token' implementation provided by a different library instead, for example Guava's [`com.google.common.reflect.TypeToken`](https://javadoc.io/doc/com.google.guava/guava/latest/com/google/common/reflect/TypeToken.html).
+
+For backward compatibility it is possible to restore Gson's old behavior of allowing `TypeToken` to capture type variables by setting the [system property](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/System.html#setProperty(java.lang.String,java.lang.String)) `gson.allowCapturingTypeVariables` to `"true"`, **however**:
+
+- This does not solve any of the type-safety problems mentioned above; in the long term you should prefer one of the other solutions listed above. This system property might be removed in future Gson versions.
+- You should only ever set the property to `"true"`, but never to any other value or manually clear it. Otherwise this might counteract any libraries you are using which might have deliberately set the system property because they rely on its behavior.

UserGuide.md

@@ -366,7 +366,7 @@ class Event {
 
 You can serialize the collection with Gson without doing anything specific: `toJson(collection)` would write out the desired output.
 
-However, deserialization with `fromJson(json, Collection.class)` will not work since Gson has no way of knowing how to map the input to the types. Gson requires that you provide a genericised version of collection type in `fromJson()`. So, you have three options:
+However, deserialization with `fromJson(json, Collection.class)` will not work since Gson has no way of knowing how to map the input to the types. Gson requires that you provide a genericized version of the collection type in `fromJson()`. So, you have three options:
 
 1. Use Gson's parser API (low-level streaming parser or the DOM parser JsonParser) to parse the array elements and then use `Gson.fromJson()` on each of the array elements.This is the preferred approach. [Here is an example](extras/src/main/java/com/google/gson/extras/examples/rawcollections/RawCollectionsExample.java) that demonstrates how to do this.
 
@@ -389,7 +389,7 @@ You can also find source code for some commonly used classes such as JodaTime at
 
 ### Custom Serialization and Deserialization
 
-Sometimes default representation is not what you want. This is often the case when dealing with library classes (DateTime, etc).
+Sometimes the default representation is not what you want. This is often the case when dealing with library classes (DateTime, etc.).
 Gson allows you to register your own custom serializers and deserializers. This is done by defining two parts:
 
 * JSON Serializers: Need to define custom serialization for an object
@@ -405,7 +405,9 @@ gson.registerTypeAdapter(MyType.class, new MyDeserializer());
 gson.registerTypeAdapter(MyType.class, new MyInstanceCreator());
 ```
 
-`registerTypeAdapter` call checks if the type adapter implements more than one of these interfaces and register it for all of them.
+`registerTypeAdapter` call checks
+1. if the type adapter implements more than one of these interfaces, in that case it registers the adapter for all of them.
+2. if the type adapter is for the Object class or JsonElement or any of its subclasses, in that case it throws IllegalArgumentException because overriding the built-in adapters for these types is not supported.
 
 #### Writing a Serializer
 
@@ -741,7 +743,7 @@ In addition Gson's object model and data binding, you can use Gson to read from
 
 ## Issues in Designing Gson
 
-See the [Gson design document](GsonDesignDocument.md "Gson design document") for a discussion of issues we faced while designing Gson. It also include a comparison of Gson with other Java libraries that can be used for JSON conversion.
+See the [Gson design document](GsonDesignDocument.md "Gson design document") for a discussion of issues we faced while designing Gson. It also includes a comparison of Gson with other Java libraries that can be used for JSON conversion.
 
 ## Future Enhancements to Gson
 

examples/android-proguard-example/src/com/google/gson/examples/android/GsonProguardExampleActivity.java

@@ -41,13 +41,13 @@ public class GsonProguardExampleActivity extends Activity {
     Cart cart = buildCart();
     StringBuilder sb = new StringBuilder();
     sb.append("Gson.toJson() example: \n");
-    sb.append("  Cart Object: ").append(cart).append("\n");
-    sb.append("  Cart JSON: ").append(gson.toJson(cart)).append("\n");
+    sb.append("  Cart Object: ").append(cart).append('\n');
+    sb.append("  Cart JSON: ").append(gson.toJson(cart)).append('\n');
     sb.append("\n\nGson.fromJson() example: \n");
     String json = "{buyer:'Happy Camper',creditCard:'4111-1111-1111-1111',"
       + "lineItems:[{name:'nails',priceInMicros:100000,quantity:100,currencyCode:'USD'}]}";
-    sb.append("Cart JSON: ").append(json).append("\n");
-    sb.append("Cart Object: ").append(gson.fromJson(json, Cart.class)).append("\n");
+    sb.append("Cart JSON: ").append(json).append('\n');
+    sb.append("Cart Object: ").append(gson.fromJson(json, Cart.class)).append('\n');
     tv.setText(sb.toString());
     tv.invalidate();
   }

gson/pom.xml

@@ -33,6 +33,12 @@
     </license>
   </licenses>
 
+  <properties>
+    <!-- Make the build reproducible, see root `pom.xml` -->
+    <!-- This is duplicated here because that is recommended by `artifact:check-buildplan` -->
+    <project.build.outputTimestamp>2023-01-01T00:00:00Z</project.build.outputTimestamp>
+  </properties>
+
   <dependencies>
     <!--
     errorprone was removed due to JPMS:
@@ -54,7 +60,7 @@
     <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava-testlib</artifactId>
-      <version>32.1.2-jre</version>
+      <version>33.0.0-jre</version>
       <scope>test</scope>
     </dependency>
   </dependencies>
@@ -67,7 +73,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>templating-maven-plugin</artifactId>
-        <version>1.0.0</version>
+        <version>3.0.0</version>
         <executions>
           <execution>
             <id>filtering-java-templates</id>
@@ -135,11 +141,11 @@
         <artifactId>maven-surefire-plugin</artifactId>
         <configuration>
           <!-- Deny illegal access, this is required for ReflectionAccessTest -->
-          <!-- Requires Java >= 9; Important: In case future Java versions 
-            don't support this flag anymore, don't remove it unless CI also runs with 
-            that Java version. Ideally would use toolchain to specify that this should 
-            run with e.g. Java 11, but Maven toolchain requirements (unlike Gradle ones) 
-            don't seem to be portable (every developer would have to set up toolchain 
+          <!-- Requires Java >= 9; Important: In case future Java versions
+            don't support this flag anymore, don't remove it unless CI also runs with
+            that Java version. Ideally would use toolchain to specify that this should
+            run with e.g. Java 11, but Maven toolchain requirements (unlike Gradle ones)
+            don't seem to be portable (every developer would have to set up toolchain
             configuration locally). -->
           <argLine>--illegal-access=deny</argLine>
         </configuration>
@@ -189,7 +195,7 @@
       <plugin>
         <groupId>org.moditect</groupId>
         <artifactId>moditect-maven-plugin</artifactId>
-        <version>1.0.0.RC2</version>
+        <version>1.1.0</version>
         <executions>
           <execution>
             <id>add-module-info</id>

gson/src/main/java-templates/com/google/gson/internal/GsonBuildConfig.java

@@ -17,8 +17,8 @@
 package com.google.gson.internal;
 
 /**
- * Build configuration for Gson. This file is automatically populated by
- * templating-maven-plugin and .java/.class files are generated for use in Gson.
+ * Build configuration for Gson. This file is automatically populated by templating-maven-plugin and
+ * .java/.class files are generated for use in Gson.
  *
  * @author Inderjeet Singh
  */
@@ -28,5 +28,5 @@ public final class GsonBuildConfig {
   /** This field is automatically populated by Maven when a build is triggered */
   public static final String VERSION = "${project.version}";
 
-  private GsonBuildConfig() { }
+  private GsonBuildConfig() {}
 }

gson/src/main/java/com/google/gson/ExclusionStrategy.java

@@ -17,12 +17,13 @@
 package com.google.gson;
 
 /**
- * A strategy (or policy) definition that is used to decide whether or not a field or
- * class should be serialized or deserialized as part of the JSON output/input.
+ * A strategy (or policy) definition that is used to decide whether or not a field or class should
+ * be serialized or deserialized as part of the JSON output/input.
  *
  * <p>The following are a few examples that shows how you can use this exclusion mechanism.
  *
  * <p><strong>Exclude fields and objects based on a particular class type:</strong>
+ *
  * <pre class="code">
  * private static class SpecificClassExclusionStrategy implements ExclusionStrategy {
  *   private final Class&lt;?&gt; excludedThisClass;
@@ -42,6 +43,7 @@ package com.google.gson;
  * </pre>
  *
  * <p><strong>Excludes fields and objects based on a particular annotation:</strong>
+ *
  * <pre class="code">
  * public &#64;interface FooAnnotation {
  *   // some implementation here
@@ -59,9 +61,10 @@ package com.google.gson;
  * }
  * </pre>
  *
- * <p>Now if you want to configure {@code Gson} to use a user defined exclusion strategy, then
- * the {@code GsonBuilder} is required. The following is an example of how you can use the
- * {@code GsonBuilder} to configure Gson to use one of the above samples:
+ * <p>Now if you want to configure {@code Gson} to use a user defined exclusion strategy, then the
+ * {@code GsonBuilder} is required. The following is an example of how you can use the {@code
+ * GsonBuilder} to configure Gson to use one of the above samples:
+ *
  * <pre class="code">
  * ExclusionStrategy excludeStrings = new UserDefinedExclusionStrategy(String.class);
  * Gson gson = new GsonBuilder()
@@ -70,10 +73,10 @@ package com.google.gson;
  * </pre>
  *
  * <p>For certain model classes, you may only want to serialize a field, but exclude it for
- * deserialization. To do that, you can write an {@code ExclusionStrategy} as per normal;
- * however, you would register it with the
- * {@link GsonBuilder#addDeserializationExclusionStrategy(ExclusionStrategy)} method.
- * For example:
+ * deserialization. To do that, you can write an {@code ExclusionStrategy} as per normal; however,
+ * you would register it with the {@link
+ * GsonBuilder#addDeserializationExclusionStrategy(ExclusionStrategy)} method. For example:
+ *
  * <pre class="code">
  * ExclusionStrategy excludeStrings = new UserDefinedExclusionStrategy(String.class);
  * Gson gson = new GsonBuilder()
@@ -83,11 +86,9 @@ package com.google.gson;
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
- *
  * @see GsonBuilder#setExclusionStrategies(ExclusionStrategy...)
  * @see GsonBuilder#addDeserializationExclusionStrategy(ExclusionStrategy)
  * @see GsonBuilder#addSerializationExclusionStrategy(ExclusionStrategy)
- *
  * @since 1.4
  */
 public interface ExclusionStrategy {

gson/src/main/java/com/google/gson/FieldAttributes.java

@@ -30,7 +30,6 @@ import java.util.Objects;
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
- *
  * @since 1.4
  */
 public final class FieldAttributes {
@@ -64,7 +63,10 @@ public final class FieldAttributes {
   }
 
   /**
+   * Returns the declared generic type of the field.
+   *
    * <p>For example, assume the following class definition:
+   *
    * <pre class="code">
    * public class Foo {
    *   private String bar;
@@ -74,8 +76,8 @@ public final class FieldAttributes {
    * Type listParameterizedType = new TypeToken&lt;List&lt;String&gt;&gt;() {}.getType();
    * </pre>
    *
-   * <p>This method would return {@code String.class} for the {@code bar} field and
-   * {@code listParameterizedType} for the {@code red} field.
+   * <p>This method would return {@code String.class} for the {@code bar} field and {@code
+   * listParameterizedType} for the {@code red} field.
    *
    * @return the specific type declared for this field
    */
@@ -87,6 +89,7 @@ public final class FieldAttributes {
    * Returns the {@code Class} object that was declared for this field.
    *
    * <p>For example, assume the following class definition:
+   *
    * <pre class="code">
    * public class Foo {
    *   private String bar;
@@ -94,8 +97,8 @@ public final class FieldAttributes {
    * }
    * </pre>
    *
-   * <p>This method would return {@code String.class} for the {@code bar} field and
-   * {@code List.class} for the {@code red} field.
+   * <p>This method would return {@code String.class} for the {@code bar} field and {@code
+   * List.class} for the {@code red} field.
    *
    * @return the specific class object that was declared for the field
    */
@@ -104,8 +107,8 @@ public final class FieldAttributes {
   }
 
   /**
-   * Return the {@code T} annotation object from this field if it exist; otherwise returns
-   * {@code null}.
+   * Returns the {@code T} annotation object from this field if it exists; otherwise returns {@code
+   * null}.
    *
    * @param annotation the class of the annotation that will be retrieved
    * @return the annotation instance if it is bound to the field; otherwise {@code null}
@@ -115,7 +118,7 @@ public final class FieldAttributes {
   }
 
   /**
-   * Return the annotations that are present on this field.
+   * Returns the annotations that are present on this field.
    *
    * @return an array of all the annotations set on the field
    * @since 1.4
@@ -128,6 +131,7 @@ public final class FieldAttributes {
    * Returns {@code true} if the field is defined with the {@code modifier}.
    *
    * <p>This method is meant to be called as:
+   *
    * <pre class="code">
    * boolean hasPublicModifier = fieldAttribute.hasModifier(java.lang.reflect.Modifier.PUBLIC);
    * </pre>

gson/src/main/java/com/google/gson/FieldNamingPolicy.java

@@ -20,150 +20,161 @@ import java.lang.reflect.Field;
 import java.util.Locale;
 
 /**
- * An enumeration that defines a few standard naming conventions for JSON field names.
- * This enumeration should be used in conjunction with {@link com.google.gson.GsonBuilder}
- * to configure a {@link com.google.gson.Gson} instance to properly translate Java field
- * names into the desired JSON field names.
+ * An enumeration that defines a few standard naming conventions for JSON field names. This
+ * enumeration should be used in conjunction with {@link com.google.gson.GsonBuilder} to configure a
+ * {@link com.google.gson.Gson} instance to properly translate Java field names into the desired
+ * JSON field names.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
 public enum FieldNamingPolicy implements FieldNamingStrategy {
 
-  /**
-   * Using this naming policy with Gson will ensure that the field name is
-   * unchanged.
-   */
+  /** Using this naming policy with Gson will ensure that the field name is unchanged. */
   IDENTITY() {
-    @Override public String translateName(Field f) {
+    @Override
+    public String translateName(Field f) {
       return f.getName();
     }
   },
 
   /**
-   * Using this naming policy with Gson will ensure that the first "letter" of the Java
-   * field name is capitalized when serialized to its JSON form.
+   * Using this naming policy with Gson will ensure that the first "letter" of the Java field name
+   * is capitalized when serialized to its JSON form.
+   *
+   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":
    *
-   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":</p>
    * <ul>
-   *   <li>someFieldName ---&gt; SomeFieldName</li>
-   *   <li>_someFieldName ---&gt; _SomeFieldName</li>
+   *   <li>someFieldName ---&gt; SomeFieldName
+   *   <li>_someFieldName ---&gt; _SomeFieldName
    * </ul>
    */
   UPPER_CAMEL_CASE() {
-    @Override public String translateName(Field f) {
+    @Override
+    public String translateName(Field f) {
       return upperCaseFirstLetter(f.getName());
     }
   },
 
   /**
-   * Using this naming policy with Gson will ensure that the first "letter" of the Java
-   * field name is capitalized when serialized to its JSON form and the words will be
-   * separated by a space.
+   * Using this naming policy with Gson will ensure that the first "letter" of the Java field name
+   * is capitalized when serialized to its JSON form and the words will be separated by a space.
+   *
+   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":
    *
-   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":</p>
    * <ul>
-   *   <li>someFieldName ---&gt; Some Field Name</li>
-   *   <li>_someFieldName ---&gt; _Some Field Name</li>
+   *   <li>someFieldName ---&gt; Some Field Name
+   *   <li>_someFieldName ---&gt; _Some Field Name
    * </ul>
    *
    * @since 1.4
    */
   UPPER_CAMEL_CASE_WITH_SPACES() {
-    @Override public String translateName(Field f) {
+    @Override
+    public String translateName(Field f) {
       return upperCaseFirstLetter(separateCamelCase(f.getName(), ' '));
     }
   },
 
   /**
-   * Using this naming policy with Gson will modify the Java Field name from its camel cased
-   * form to an upper case field name where each word is separated by an underscore (_).
+   * Using this naming policy with Gson will modify the Java Field name from its camel cased form to
+   * an upper case field name where each word is separated by an underscore (_).
+   *
+   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":
    *
-   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":</p>
    * <ul>
-   *   <li>someFieldName ---&gt; SOME_FIELD_NAME</li>
-   *   <li>_someFieldName ---&gt; _SOME_FIELD_NAME</li>
-   *   <li>aStringField ---&gt; A_STRING_FIELD</li>
-   *   <li>aURL ---&gt; A_U_R_L</li>
+   *   <li>someFieldName ---&gt; SOME_FIELD_NAME
+   *   <li>_someFieldName ---&gt; _SOME_FIELD_NAME
+   *   <li>aStringField ---&gt; A_STRING_FIELD
+   *   <li>aURL ---&gt; A_U_R_L
    * </ul>
    *
    * @since 2.9.0
    */
   UPPER_CASE_WITH_UNDERSCORES() {
-    @Override public String translateName(Field f) {
+    @Override
+    public String translateName(Field f) {
       return separateCamelCase(f.getName(), '_').toUpperCase(Locale.ENGLISH);
     }
   },
 
   /**
-   * Using this naming policy with Gson will modify the Java Field name from its camel cased
-   * form to a lower case field name where each word is separated by an underscore (_).
+   * Using this naming policy with Gson will modify the Java Field name from its camel cased form to
+   * a lower case field name where each word is separated by an underscore (_).
+   *
+   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":
    *
-   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":</p>
    * <ul>
-   *   <li>someFieldName ---&gt; some_field_name</li>
-   *   <li>_someFieldName ---&gt; _some_field_name</li>
-   *   <li>aStringField ---&gt; a_string_field</li>
-   *   <li>aURL ---&gt; a_u_r_l</li>
+   *   <li>someFieldName ---&gt; some_field_name
+   *   <li>_someFieldName ---&gt; _some_field_name
+   *   <li>aStringField ---&gt; a_string_field
+   *   <li>aURL ---&gt; a_u_r_l
    * </ul>
    */
   LOWER_CASE_WITH_UNDERSCORES() {
-    @Override public String translateName(Field f) {
+    @Override
+    public String translateName(Field f) {
       return separateCamelCase(f.getName(), '_').toLowerCase(Locale.ENGLISH);
     }
   },
 
   /**
-   * Using this naming policy with Gson will modify the Java Field name from its camel cased
-   * form to a lower case field name where each word is separated by a dash (-).
+   * Using this naming policy with Gson will modify the Java Field name from its camel cased form to
+   * a lower case field name where each word is separated by a dash (-).
+   *
+   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":
    *
-   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":</p>
    * <ul>
-   *   <li>someFieldName ---&gt; some-field-name</li>
-   *   <li>_someFieldName ---&gt; _some-field-name</li>
-   *   <li>aStringField ---&gt; a-string-field</li>
-   *   <li>aURL ---&gt; a-u-r-l</li>
+   *   <li>someFieldName ---&gt; some-field-name
+   *   <li>_someFieldName ---&gt; _some-field-name
+   *   <li>aStringField ---&gt; a-string-field
+   *   <li>aURL ---&gt; a-u-r-l
    * </ul>
+   *
    * Using dashes in JavaScript is not recommended since dash is also used for a minus sign in
    * expressions. This requires that a field named with dashes is always accessed as a quoted
-   * property like {@code myobject['my-field']}. Accessing it as an object field
-   * {@code myobject.my-field} will result in an unintended JavaScript expression.
+   * property like {@code myobject['my-field']}. Accessing it as an object field {@code
+   * myobject.my-field} will result in an unintended JavaScript expression.
    *
    * @since 1.4
    */
   LOWER_CASE_WITH_DASHES() {
-    @Override public String translateName(Field f) {
+    @Override
+    public String translateName(Field f) {
       return separateCamelCase(f.getName(), '-').toLowerCase(Locale.ENGLISH);
     }
   },
 
   /**
-   * Using this naming policy with Gson will modify the Java Field name from its camel cased
-   * form to a lower case field name where each word is separated by a dot (.).
+   * Using this naming policy with Gson will modify the Java Field name from its camel cased form to
+   * a lower case field name where each word is separated by a dot (.).
+   *
+   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":
    *
-   * <p>Here are a few examples of the form "Java Field Name" ---&gt; "JSON Field Name":</p>
    * <ul>
-   *   <li>someFieldName ---&gt; some.field.name</li>
-   *   <li>_someFieldName ---&gt; _some.field.name</li>
-   *   <li>aStringField ---&gt; a.string.field</li>
-   *   <li>aURL ---&gt; a.u.r.l</li>
+   *   <li>someFieldName ---&gt; some.field.name
+   *   <li>_someFieldName ---&gt; _some.field.name
+   *   <li>aStringField ---&gt; a.string.field
+   *   <li>aURL ---&gt; a.u.r.l
    * </ul>
+   *
    * Using dots in JavaScript is not recommended since dot is also used for a member sign in
-   * expressions. This requires that a field named with dots is always accessed as a quoted
-   * property like {@code myobject['my.field']}. Accessing it as an object field
-   * {@code myobject.my.field} will result in an unintended JavaScript expression.
+   * expressions. This requires that a field named with dots is always accessed as a quoted property
+   * like {@code myobject['my.field']}. Accessing it as an object field {@code myobject.my.field}
+   * will result in an unintended JavaScript expression.
    *
    * @since 2.8.4
    */
   LOWER_CASE_WITH_DOTS() {
-    @Override public String translateName(Field f) {
+    @Override
+    public String translateName(Field f) {
       return separateCamelCase(f.getName(), '.').toLowerCase(Locale.ENGLISH);
     }
   };
 
   /**
-   * Converts the field name that uses camel-case define word separation into
-   * separate words that are separated by the provided {@code separator}.
+   * Converts the field name that uses camel-case define word separation into separate words that
+   * are separated by the provided {@code separator}.
    */
   static String separateCamelCase(String name, char separator) {
     StringBuilder translation = new StringBuilder();
@@ -177,9 +188,7 @@ public enum FieldNamingPolicy implements FieldNamingStrategy {
     return translation.toString();
   }
 
-  /**
-   * Ensures the JSON field names begins with an upper case letter.
-   */
+  /** Ensures the JSON field names begins with an upper case letter. */
   static String upperCaseFirstLetter(String s) {
     int length = s.length();
     for (int i = 0; i < length; i++) {

gson/src/main/java/com/google/gson/FieldNamingStrategy.java

@@ -20,8 +20,8 @@ import java.lang.reflect.Field;
 
 /**
  * A mechanism for providing custom field naming in Gson. This allows the client code to translate
- * field names into a particular convention that is not supported as a normal Java field
- * declaration rules. For example, Java does not support "-" characters in a field name.
+ * field names into a particular convention that is not supported as a normal Java field declaration
+ * rules. For example, Java does not support "-" characters in a field name.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch

gson/src/main/java/com/google/gson/FormattingStyle.java

@@ -22,8 +22,9 @@ import java.util.Objects;
 /**
  * A class used to control what the serialization output looks like.
  *
- * <p>It currently has the following configuration methods, but more methods
- * might be added in the future:
+ * <p>It currently has the following configuration methods, but more methods might be added in the
+ * future:
+ *
  * <ul>
  *   <li>{@link #withNewline(String)}
  *   <li>{@link #withIndent(String)}
@@ -33,7 +34,6 @@ import java.util.Objects;
  * @see GsonBuilder#setFormattingStyle(FormattingStyle)
  * @see JsonWriter#setFormattingStyle(FormattingStyle)
  * @see <a href="https://en.wikipedia.org/wiki/Newline">Wikipedia Newline article</a>
- *
  * @since $next-version$
  */
 public class FormattingStyle {
@@ -43,6 +43,7 @@ public class FormattingStyle {
 
   /**
    * The default compact formatting style:
+   *
    * <ul>
    *   <li>no newline
    *   <li>no indent
@@ -53,14 +54,14 @@ public class FormattingStyle {
 
   /**
    * The default pretty printing formatting style:
+   *
    * <ul>
    *   <li>{@code "\n"} as newline
    *   <li>two spaces as indent
    *   <li>a space between {@code ':'} and the subsequent value
    * </ul>
    */
-  public static final FormattingStyle PRETTY =
-      new FormattingStyle("\n", "  ", true);
+  public static final FormattingStyle PRETTY = new FormattingStyle("\n", "  ", true);
 
   private FormattingStyle(String newline, String indent, boolean spaceAfterSeparators) {
     Objects.requireNonNull(newline, "newline == null");
@@ -81,11 +82,11 @@ public class FormattingStyle {
   /**
    * Creates a {@link FormattingStyle} with the specified newline setting.
    *
-   * <p>It can be used to accommodate certain OS convention, for example
-   * hardcode {@code "\n"} for Linux and macOS, {@code "\r\n"} for Windows, or
-   * call {@link java.lang.System#lineSeparator()} to match the current OS.</p>
+   * <p>It can be used to accommodate certain OS convention, for example hardcode {@code "\n"} for
+   * Linux and macOS, {@code "\r\n"} for Windows, or call {@link java.lang.System#lineSeparator()}
+   * to match the current OS.
    *
-   * <p>Only combinations of {@code \n} and {@code \r} are allowed.</p>
+   * <p>Only combinations of {@code \n} and {@code \r} are allowed.
    *
    * @param newline the string value that will be used as newline.
    * @return a newly created {@link FormattingStyle}
@@ -97,7 +98,7 @@ public class FormattingStyle {
   /**
    * Creates a {@link FormattingStyle} with the specified indent string.
    *
-   * <p>Only combinations of spaces and tabs allowed in indent.</p>
+   * <p>Only combinations of spaces and tabs allowed in indent.
    *
    * @param indent the string value that will be used as indent.
    * @return a newly created {@link FormattingStyle}
@@ -107,12 +108,12 @@ public class FormattingStyle {
   }
 
   /**
-   * Creates a {@link FormattingStyle} which either uses a space after
-   * the separators {@code ','} and {@code ':'} in the JSON output, or not.
+   * Creates a {@link FormattingStyle} which either uses a space after the separators {@code ','}
+   * and {@code ':'} in the JSON output, or not.
    *
-   * <p>This setting has no effect on the {@linkplain #withNewline(String) configured newline}.
-   * If a non-empty newline is configured, it will always be added after
-   * {@code ','} and no space is added after the {@code ','} in that case.</p>
+   * <p>This setting has no effect on the {@linkplain #withNewline(String) configured newline}. If a
+   * non-empty newline is configured, it will always be added after {@code ','} and no space is
+   * added after the {@code ','} in that case.
    *
    * @param spaceAfterSeparators whether to output a space after {@code ','} and {@code ':'}.
    * @return a newly created {@link FormattingStyle}
@@ -139,9 +140,7 @@ public class FormattingStyle {
     return this.indent;
   }
 
-  /**
-   * Returns whether a space will be used after {@code ','} and {@code ':'}.
-   */
+  /** Returns whether a space will be used after {@code ','} and {@code ':'}. */
   public boolean usesSpaceAfterSeparators() {
     return this.spaceAfterSeparators;
   }

gson/src/main/java/com/google/gson/GsonBuilder.java

@@ -31,6 +31,7 @@ import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import java.lang.reflect.Type;
 import java.text.DateFormat;
+import java.text.SimpleDateFormat;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -41,10 +42,10 @@ import java.util.Map;
 import java.util.Objects;
 
 /**
- * <p>Use this builder to construct a {@link Gson} instance when you need to set configuration
- * options other than the default. For {@link Gson} with default configuration, it is simpler to
- * use {@code new Gson()}. {@code GsonBuilder} is best used by creating it, and then invoking its
- * various configuration methods, and finally calling create.</p>
+ * Use this builder to construct a {@link Gson} instance when you need to set configuration options
+ * other than the default. For {@link Gson} with default configuration, it is simpler to use {@code
+ * new Gson()}. {@code GsonBuilder} is best used by creating it, and then invoking its various
+ * configuration methods, and finally calling create.
  *
  * <p>The following example shows how to use the {@code GsonBuilder} to construct a Gson instance:
  *
@@ -53,7 +54,7 @@ import java.util.Objects;
  *     .registerTypeAdapter(Id.class, new IdTypeAdapter())
  *     .enableComplexMapKeySerialization()
  *     .serializeNulls()
- *     .setDateFormat(DateFormat.LONG)
+ *     .setDateFormat(DateFormat.LONG, DateFormat.LONG)
  *     .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
  *     .setPrettyPrinting()
  *     .setVersion(1.0)
@@ -61,15 +62,16 @@ import java.util.Objects;
  * </pre>
  *
  * <p>Notes:
+ *
  * <ul>
- * <li>The order of invocation of configuration methods does not matter.</li>
- * <li>The default serialization of {@link Date} and its subclasses in Gson does
- *  not contain time-zone information. So, if you are using date/time instances,
- *  use {@code GsonBuilder} and its {@code setDateFormat} methods.</li>
- * <li>By default no explicit {@link Strictness} is set; some of the {@link Gson} methods
- *  behave as if {@link Strictness#LEGACY_STRICT} was used whereas others behave as
- *  if {@link Strictness#LENIENT} was used. Prefer explicitly setting a strictness
- *  with {@link #setStrictness(Strictness)} to avoid this legacy behavior.
+ *   <li>The order of invocation of configuration methods does not matter.
+ *   <li>The default serialization of {@link Date} and its subclasses in Gson does not contain
+ *       time-zone information. So, if you are using date/time instances, use {@code GsonBuilder}
+ *       and its {@code setDateFormat} methods.
+ *   <li>By default no explicit {@link Strictness} is set; some of the {@link Gson} methods behave
+ *       as if {@link Strictness#LEGACY_STRICT} was used whereas others behave as if {@link
+ *       Strictness#LENIENT} was used. Prefer explicitly setting a strictness with {@link
+ *       #setStrictness(Strictness)} to avoid this legacy behavior.
  * </ul>
  *
  * @author Inderjeet Singh
@@ -82,8 +84,10 @@ public final class GsonBuilder {
   private FieldNamingStrategy fieldNamingPolicy = FieldNamingPolicy.IDENTITY;
   private final Map<Type, InstanceCreator<?>> instanceCreators = new HashMap<>();
   private final List<TypeAdapterFactory> factories = new ArrayList<>();
+
   /** tree-style hierarchy factories. These come after factories for backwards compatibility. */
   private final List<TypeAdapterFactory> hierarchyFactories = new ArrayList<>();
+
   private boolean serializeNulls = DEFAULT_SERIALIZE_NULLS;
   private String datePattern = DEFAULT_DATE_PATTERN;
   private int dateStyle = DateFormat.DEFAULT;
@@ -103,16 +107,14 @@ public final class GsonBuilder {
 
   /**
    * Creates a GsonBuilder instance that can be used to build Gson with various configuration
-   * settings. GsonBuilder follows the builder pattern, and it is typically used by first
-   * invoking various configuration methods to set desired options, and finally calling
-   * {@link #create()}.
+   * settings. GsonBuilder follows the builder pattern, and it is typically used by first invoking
+   * various configuration methods to set desired options, and finally calling {@link #create()}.
    */
-  public GsonBuilder() {
-  }
+  public GsonBuilder() {}
 
   /**
-   * Constructs a GsonBuilder instance from a Gson instance. The newly constructed GsonBuilder
-   * has the same configuration as the previously built Gson instance.
+   * Constructs a GsonBuilder instance from a Gson instance. The newly constructed GsonBuilder has
+   * the same configuration as the previously built Gson instance.
    *
    * @param gson the gson instance whose configuration should be applied to a new GsonBuilder.
    */
@@ -142,13 +144,13 @@ public final class GsonBuilder {
   }
 
   /**
-   * Configures Gson to enable versioning support. Versioning support works based on the
-   * annotation types {@link Since} and {@link Until}. It allows including or excluding fields
-   * and classes based on the specified version. See the documentation of these annotation
-   * types for more information.
+   * Configures Gson to enable versioning support. Versioning support works based on the annotation
+   * types {@link Since} and {@link Until}. It allows including or excluding fields and classes
+   * based on the specified version. See the documentation of these annotation types for more
+   * information.
    *
-   * <p>By default versioning support is disabled and usage of {@code @Since} and {@code @Until}
-   * has no effect.
+   * <p>By default versioning support is disabled and usage of {@code @Since} and {@code @Until} has
+   * no effect.
    *
    * @param version the version number to use.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -169,13 +171,13 @@ public final class GsonBuilder {
    * Gson will exclude all fields marked {@code transient} or {@code static}. This method will
    * override that behavior.
    *
-   * <p>This is a convenience method which behaves as if an {@link ExclusionStrategy} which
-   * excludes these fields was {@linkplain #setExclusionStrategies(ExclusionStrategy...) registered with this builder}.
+   * <p>This is a convenience method which behaves as if an {@link ExclusionStrategy} which excludes
+   * these fields was {@linkplain #setExclusionStrategies(ExclusionStrategy...) registered with this
+   * builder}.
    *
-   * @param modifiers the field modifiers. You must use the modifiers specified in the
-   * {@link java.lang.reflect.Modifier} class. For example,
-   * {@link java.lang.reflect.Modifier#TRANSIENT},
-   * {@link java.lang.reflect.Modifier#STATIC}.
+   * @param modifiers the field modifiers. You must use the modifiers specified in the {@link
+   *     java.lang.reflect.Modifier} class. For example, {@link
+   *     java.lang.reflect.Modifier#TRANSIENT}, {@link java.lang.reflect.Modifier#STATIC}.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
    */
   public GsonBuilder excludeFieldsWithModifiers(int... modifiers) {
@@ -186,9 +188,8 @@ public final class GsonBuilder {
 
   /**
    * Makes the output JSON non-executable in Javascript by prefixing the generated JSON with some
-   * special text. This prevents attacks from third-party sites through script sourcing. See
-   * <a href="http://code.google.com/p/google-gson/issues/detail?id=42">Gson Issue 42</a>
-   * for details.
+   * special text. This prevents attacks from third-party sites through script sourcing. See <a
+   * href="http://code.google.com/p/google-gson/issues/detail?id=42">Gson Issue 42</a> for details.
    *
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
    * @since 1.3
@@ -203,7 +204,8 @@ public final class GsonBuilder {
    * that do not have the {@link com.google.gson.annotations.Expose} annotation.
    *
    * <p>This is a convenience method which behaves as if an {@link ExclusionStrategy} which excludes
-   * these fields was {@linkplain #setExclusionStrategies(ExclusionStrategy...) registered with this builder}.
+   * these fields was {@linkplain #setExclusionStrategies(ExclusionStrategy...) registered with this
+   * builder}.
    *
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
    */
@@ -213,7 +215,7 @@ public final class GsonBuilder {
   }
 
   /**
-   * Configure Gson to serialize null fields. By default, Gson omits all fields that are null
+   * Configures Gson to serialize null fields. By default, Gson omits all fields that are null
    * during serialization.
    *
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -225,79 +227,82 @@ public final class GsonBuilder {
   }
 
   /**
-   * Enabling this feature will only change the serialized form if the map key is
-   * a complex type (i.e. non-primitive) in its <strong>serialized</strong> JSON
-   * form. The default implementation of map serialization uses {@code toString()}
-   * on the key; however, when this is called then one of the following cases
-   * apply:
+   * Configures Gson to serialize {@code Map} objects with complex keys as JSON arrays. Enabling
+   * this feature will only change the serialized form if the map key is a complex type (i.e.
+   * non-primitive) in its <strong>serialized</strong> JSON form. The default implementation of map
+   * serialization uses {@code toString()} on the key; however, when this is called then one of the
+   * following cases apply:
    *
    * <p><b>Maps as JSON objects</b>
    *
-   * <p>For this case, assume that a type adapter is registered to serialize and
-   * deserialize some {@code Point} class, which contains an x and y coordinate,
-   * to/from the JSON Primitive string value {@code "(x,y)"}. The Java map would
-   * then be serialized as a {@link JsonObject}.
+   * <p>For this case, assume that a type adapter is registered to serialize and deserialize some
+   * {@code Point} class, which contains an x and y coordinate, to/from the JSON Primitive string
+   * value {@code "(x,y)"}. The Java map would then be serialized as a {@link JsonObject}.
    *
    * <p>Below is an example:
-   * <pre>  {@code
-   *   Gson gson = new GsonBuilder()
-   *       .register(Point.class, new MyPointTypeAdapter())
-   *       .enableComplexMapKeySerialization()
-   *       .create();
    *
-   *   Map<Point, String> original = new LinkedHashMap<>();
-   *   original.put(new Point(5, 6), "a");
-   *   original.put(new Point(8, 8), "b");
-   *   System.out.println(gson.toJson(original, type));
+   * <pre>{@code
+   * Gson gson = new GsonBuilder()
+   *     .register(Point.class, new MyPointTypeAdapter())
+   *     .enableComplexMapKeySerialization()
+   *     .create();
+   *
+   * Map<Point, String> original = new LinkedHashMap<>();
+   * original.put(new Point(5, 6), "a");
+   * original.put(new Point(8, 8), "b");
+   * System.out.println(gson.toJson(original, type));
    * }</pre>
-   * The above code prints this JSON object:<pre>  {@code
-   *   {
-   *     "(5,6)": "a",
-   *     "(8,8)": "b"
-   *   }
+   *
+   * The above code prints this JSON object:
+   *
+   * <pre>{@code
+   * {
+   *   "(5,6)": "a",
+   *   "(8,8)": "b"
+   * }
    * }</pre>
    *
    * <p><b>Maps as JSON arrays</b>
    *
-   * <p>For this case, assume that a type adapter was NOT registered for some
-   * {@code Point} class, but rather the default Gson serialization is applied.
-   * In this case, some {@code new Point(2,3)} would serialize as {@code
-   * {"x":2,"y":3}}.
+   * <p>For this case, assume that a type adapter was NOT registered for some {@code Point} class,
+   * but rather the default Gson serialization is applied. In this case, some {@code new Point(2,3)}
+   * would serialize as {@code {"x":2,"y":3}}.
    *
-   * <p>Given the assumption above, a {@code Map<Point, String>} will be
-   * serialized as an array of arrays (can be viewed as an entry set of pairs).
+   * <p>Given the assumption above, a {@code Map<Point, String>} will be serialized as an array of
+   * arrays (can be viewed as an entry set of pairs).
    *
    * <p>Below is an example of serializing complex types as JSON arrays:
-   * <pre> {@code
-   *   Gson gson = new GsonBuilder()
-   *       .enableComplexMapKeySerialization()
-   *       .create();
    *
-   *   Map<Point, String> original = new LinkedHashMap<>();
-   *   original.put(new Point(5, 6), "a");
-   *   original.put(new Point(8, 8), "b");
-   *   System.out.println(gson.toJson(original, type));
-   * }
-   * </pre>
+   * <pre>{@code
+   * Gson gson = new GsonBuilder()
+   *     .enableComplexMapKeySerialization()
+   *     .create();
+   *
+   * Map<Point, String> original = new LinkedHashMap<>();
+   * original.put(new Point(5, 6), "a");
+   * original.put(new Point(8, 8), "b");
+   * System.out.println(gson.toJson(original, type));
+   * }</pre>
    *
    * The JSON output would look as follows:
-   * <pre>   {@code
+   *
+   * <pre>{@code
+   * [
    *   [
-   *     [
-   *       {
-   *         "x": 5,
-   *         "y": 6
-   *       },
-   *       "a"
-   *     ],
-   *     [
-   *       {
-   *         "x": 8,
-   *         "y": 8
-   *       },
-   *       "b"
-   *     ]
+   *     {
+   *       "x": 5,
+   *       "y": 6
+   *     },
+   *     "a"
+   *   ],
+   *   [
+   *     {
+   *       "x": 8,
+   *       "y": 8
+   *     },
+   *     "b"
    *   ]
+   * ]
    * }</pre>
    *
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -325,20 +330,22 @@ public final class GsonBuilder {
   }
 
   /**
-   * Configures Gson to exclude inner classes (= non-{@code static} nested classes) during serialization
-   * and deserialization. This is a convenience method which behaves as if an {@link ExclusionStrategy}
-   * which excludes inner classes was {@linkplain #setExclusionStrategies(ExclusionStrategy...) registered with this builder}.
-   * This means inner classes will be serialized as JSON {@code null}, and will be deserialized as
-   * Java {@code null} with their JSON data being ignored. And fields with an inner class as type will
-   * be ignored during serialization and deserialization.
+   * Configures Gson to exclude inner classes (= non-{@code static} nested classes) during
+   * serialization and deserialization. This is a convenience method which behaves as if an {@link
+   * ExclusionStrategy} which excludes inner classes was {@linkplain
+   * #setExclusionStrategies(ExclusionStrategy...) registered with this builder}. This means inner
+   * classes will be serialized as JSON {@code null}, and will be deserialized as Java {@code null}
+   * with their JSON data being ignored. And fields with an inner class as type will be ignored
+   * during serialization and deserialization.
    *
    * <p>By default Gson serializes and deserializes inner classes, but ignores references to the
-   * enclosing instance. Deserialization might not be possible at all when {@link #disableJdkUnsafe()}
-   * is used (and no custom {@link InstanceCreator} is registered), or it can lead to unexpected
-   * {@code NullPointerException}s when the deserialized instance is used afterwards.
+   * enclosing instance. Deserialization might not be possible at all when {@link
+   * #disableJdkUnsafe()} is used (and no custom {@link InstanceCreator} is registered), or it can
+   * lead to unexpected {@code NullPointerException}s when the deserialized instance is used
+   * afterwards.
    *
-   * <p>In general using inner classes with Gson should be avoided; they should be converted to {@code static}
-   * nested classes if possible.
+   * <p>In general using inner classes with Gson should be avoided; they should be converted to
+   * {@code static} nested classes if possible.
    *
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
    * @since 1.3
@@ -372,12 +379,12 @@ public final class GsonBuilder {
   }
 
   /**
-   * Configures Gson to apply a specific naming strategy to an object's fields during
-   * serialization and deserialization.
+   * Configures Gson to apply a specific naming strategy to an object's fields during serialization
+   * and deserialization.
    *
-   * <p>The created Gson instance might only use the field naming strategy once for a
-   * field and cache the result. It is not guaranteed that the strategy will be used
-   * again every time the value of a field is serialized or deserialized.
+   * <p>The created Gson instance might only use the field naming strategy once for a field and
+   * cache the result. It is not guaranteed that the strategy will be used again every time the
+   * value of a field is serialized or deserialized.
    *
    * @param fieldNamingStrategy the naming strategy to apply to the fields
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -416,25 +423,24 @@ public final class GsonBuilder {
 
   /**
    * Configures Gson to apply a set of exclusion strategies during both serialization and
-   * deserialization. Each of the {@code strategies} will be applied as a disjunction rule.
-   * This means that if one of the {@code strategies} suggests that a field (or class) should be
-   * skipped then that field (or object) is skipped during serialization/deserialization.
-   * The strategies are added to the existing strategies (if any); the existing strategies
-   * are not replaced.
+   * deserialization. Each of the {@code strategies} will be applied as a disjunction rule. This
+   * means that if one of the {@code strategies} suggests that a field (or class) should be skipped
+   * then that field (or object) is skipped during serialization/deserialization. The strategies are
+   * added to the existing strategies (if any); the existing strategies are not replaced.
    *
-   * <p>Fields are excluded for serialization and deserialization when
-   * {@link ExclusionStrategy#shouldSkipField(FieldAttributes) shouldSkipField} returns {@code true},
-   * or when {@link ExclusionStrategy#shouldSkipClass(Class) shouldSkipClass} returns {@code true}
-   * for the field type. Gson behaves as if the field did not exist; its value is not serialized
-   * and on deserialization if a JSON member with this name exists it is skipped by default.<br>
-   * When objects of an excluded type (as determined by
-   * {@link ExclusionStrategy#shouldSkipClass(Class) shouldSkipClass}) are serialized a
-   * JSON null is written to output, and when deserialized the JSON value is skipped and
-   * {@code null} is returned.
+   * <p>Fields are excluded for serialization and deserialization when {@link
+   * ExclusionStrategy#shouldSkipField(FieldAttributes) shouldSkipField} returns {@code true}, or
+   * when {@link ExclusionStrategy#shouldSkipClass(Class) shouldSkipClass} returns {@code true} for
+   * the field type. Gson behaves as if the field did not exist; its value is not serialized and on
+   * deserialization if a JSON member with this name exists it is skipped by default.<br>
+   * When objects of an excluded type (as determined by {@link
+   * ExclusionStrategy#shouldSkipClass(Class) shouldSkipClass}) are serialized a JSON null is
+   * written to output, and when deserialized the JSON value is skipped and {@code null} is
+   * returned.
    *
-   * <p>The created Gson instance might only use an exclusion strategy once for a field or
-   * class and cache the result. It is not guaranteed that the strategy will be used again
-   * every time the value of a field or a class is serialized or deserialized.
+   * <p>The created Gson instance might only use an exclusion strategy once for a field or class and
+   * cache the result. It is not guaranteed that the strategy will be used again every time the
+   * value of a field or a class is serialized or deserialized.
    *
    * @param strategies the set of strategy object to apply during object (de)serialization.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -449,15 +455,14 @@ public final class GsonBuilder {
   }
 
   /**
-   * Configures Gson to apply the passed in exclusion strategy during serialization.
-   * If this method is invoked numerous times with different exclusion strategy objects
-   * then the exclusion strategies that were added will be applied as a disjunction rule.
-   * This means that if one of the added exclusion strategies suggests that a field (or
-   * class) should be skipped then that field (or object) is skipped during its
-   * serialization.
+   * Configures Gson to apply the passed in exclusion strategy during serialization. If this method
+   * is invoked numerous times with different exclusion strategy objects then the exclusion
+   * strategies that were added will be applied as a disjunction rule. This means that if one of the
+   * added exclusion strategies suggests that a field (or class) should be skipped then that field
+   * (or object) is skipped during its serialization.
    *
-   * <p>See the documentation of {@link #setExclusionStrategies(ExclusionStrategy...)}
-   * for a detailed description of the effect of exclusion strategies.
+   * <p>See the documentation of {@link #setExclusionStrategies(ExclusionStrategy...)} for a
+   * detailed description of the effect of exclusion strategies.
    *
    * @param strategy an exclusion strategy to apply during serialization.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -470,15 +475,14 @@ public final class GsonBuilder {
   }
 
   /**
-   * Configures Gson to apply the passed in exclusion strategy during deserialization.
-   * If this method is invoked numerous times with different exclusion strategy objects
-   * then the exclusion strategies that were added will be applied as a disjunction rule.
-   * This means that if one of the added exclusion strategies suggests that a field (or
-   * class) should be skipped then that field (or object) is skipped during its
-   * deserialization.
+   * Configures Gson to apply the passed in exclusion strategy during deserialization. If this
+   * method is invoked numerous times with different exclusion strategy objects then the exclusion
+   * strategies that were added will be applied as a disjunction rule. This means that if one of the
+   * added exclusion strategies suggests that a field (or class) should be skipped then that field
+   * (or object) is skipped during its deserialization.
    *
-   * <p>See the documentation of {@link #setExclusionStrategies(ExclusionStrategy...)}
-   * for a detailed description of the effect of exclusion strategies.
+   * <p>See the documentation of {@link #setExclusionStrategies(ExclusionStrategy...)} for a
+   * detailed description of the effect of exclusion strategies.
    *
    * @param strategy an exclusion strategy to apply during deserialization.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -504,8 +508,9 @@ public final class GsonBuilder {
   }
 
   /**
-   * Configures Gson to output JSON that uses a certain kind of formatting style (for example newline and indent).
-   * This option only affects JSON serialization. By default Gson produces compact JSON output without any formatting.
+   * Configures Gson to output JSON that uses a certain kind of formatting style (for example
+   * newline and indent). This option only affects JSON serialization. By default Gson produces
+   * compact JSON output without any formatting.
    *
    * @param formattingStyle the formatting style to use.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -519,9 +524,8 @@ public final class GsonBuilder {
   /**
    * Sets the strictness of this builder to {@link Strictness#LENIENT}.
    *
-   * @deprecated This method is equivalent to calling {@link #setStrictness(Strictness)} with
-   * {@link Strictness#LENIENT}: {@code setStrictness(Strictness.LENIENT)}
-   *
+   * @deprecated This method is equivalent to calling {@link #setStrictness(Strictness)} with {@link
+   *     Strictness#LENIENT}: {@code setStrictness(Strictness.LENIENT)}
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern.
    * @see JsonReader#setStrictness(Strictness)
    * @see JsonWriter#setStrictness(Strictness)
@@ -535,10 +539,9 @@ public final class GsonBuilder {
   /**
    * Sets the strictness of this builder to the provided parameter.
    *
-   * <p>This changes how strict the
-   * <a href="https://www.ietf.org/rfc/rfc8259.txt">RFC 8259 JSON specification</a> is enforced when parsing or
-   * writing JSON. For details on this, refer to {@link JsonReader#setStrictness(Strictness)} and
-   * {@link JsonWriter#setStrictness(Strictness)}.</p>
+   * <p>This changes how strict the <a href="https://www.ietf.org/rfc/rfc8259.txt">RFC 8259 JSON
+   * specification</a> is enforced when parsing or writing JSON. For details on this, refer to
+   * {@link JsonReader#setStrictness(Strictness)} and {@link JsonWriter#setStrictness(Strictness)}.
    *
    * @param strictness the new strictness mode. May not be {@code null}.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern.
@@ -574,68 +577,94 @@ public final class GsonBuilder {
 
   /**
    * Configures Gson to serialize {@code Date} objects according to the pattern provided. You can
-   * call this method or {@link #setDateFormat(int)} multiple times, but only the last invocation
-   * will be used to decide the serialization format.
+   * call this method or {@link #setDateFormat(int, int)} multiple times, but only the last
+   * invocation will be used to decide the serialization format.
    *
    * <p>The date format will be used to serialize and deserialize {@link java.util.Date} and in case
-   * the {@code java.sql} module is present, also {@link java.sql.Timestamp} and {@link java.sql.Date}.
+   * the {@code java.sql} module is present, also {@link java.sql.Timestamp} and {@link
+   * java.sql.Date}.
    *
    * <p>Note that this pattern must abide by the convention provided by {@code SimpleDateFormat}
-   * class. See the documentation in {@link java.text.SimpleDateFormat} for more information on
-   * valid date and time patterns.</p>
+   * class. See the documentation in {@link SimpleDateFormat} for more information on valid date and
+   * time patterns.
    *
-   * @param pattern the pattern that dates will be serialized/deserialized to/from
+   * @param pattern the pattern that dates will be serialized/deserialized to/from; can be {@code
+   *     null} to reset the pattern
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
+   * @throws IllegalArgumentException if the pattern is invalid
    * @since 1.2
    */
   public GsonBuilder setDateFormat(String pattern) {
-    // TODO(Joel): Make this fail fast if it is an invalid date format
+    if (pattern != null) {
+      try {
+        new SimpleDateFormat(pattern);
+      } catch (IllegalArgumentException e) {
+        // Throw exception if it is an invalid date format
+        throw new IllegalArgumentException("The date pattern '" + pattern + "' is not valid", e);
+      }
+    }
     this.datePattern = pattern;
     return this;
   }
 
   /**
-   * Configures Gson to serialize {@code Date} objects according to the style value provided.
+   * Configures Gson to serialize {@code Date} objects according to the date style value provided.
    * You can call this method or {@link #setDateFormat(String)} multiple times, but only the last
-   * invocation will be used to decide the serialization format.
+   * invocation will be used to decide the serialization format. This methods leaves the current
+   * 'time style' unchanged.
    *
-   * <p>Note that this style value should be one of the predefined constants in the
-   * {@code DateFormat} class. See the documentation in {@link java.text.DateFormat} for more
-   * information on the valid style constants.</p>
+   * <p>Note that this style value should be one of the predefined constants in the {@link
+   * DateFormat} class, such as {@link DateFormat#MEDIUM}. See the documentation of the {@link
+   * DateFormat} class for more information on the valid style constants.
    *
-   * @param style the predefined date style that date objects will be serialized/deserialized
-   * to/from
+   * @deprecated Counterintuitively, despite this method taking only a 'date style' Gson will use a
+   *     format which includes both date and time, with the 'time style' being the last value set by
+   *     {@link #setDateFormat(int, int)}. Therefore prefer using {@link #setDateFormat(int, int)}
+   *     and explicitly provide the desired 'time style'.
+   * @param dateStyle the predefined date style that date objects will be serialized/deserialized
+   *     to/from
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
+   * @throws IllegalArgumentException if the style is invalid
    * @since 1.2
    */
-  public GsonBuilder setDateFormat(int style) {
-    this.dateStyle = style;
+  @Deprecated
+  public GsonBuilder setDateFormat(int dateStyle) {
+    this.dateStyle = checkDateFormatStyle(dateStyle);
     this.datePattern = null;
     return this;
   }
 
   /**
-   * Configures Gson to serialize {@code Date} objects according to the style value provided.
-   * You can call this method or {@link #setDateFormat(String)} multiple times, but only the last
+   * Configures Gson to serialize {@code Date} objects according to the style value provided. You
+   * can call this method or {@link #setDateFormat(String)} multiple times, but only the last
    * invocation will be used to decide the serialization format.
    *
-   * <p>Note that this style value should be one of the predefined constants in the
-   * {@code DateFormat} class. See the documentation in {@link java.text.DateFormat} for more
-   * information on the valid style constants.</p>
+   * <p>Note that this style value should be one of the predefined constants in the {@link
+   * DateFormat} class, such as {@link DateFormat#MEDIUM}. See the documentation of the {@link
+   * DateFormat} class for more information on the valid style constants.
    *
    * @param dateStyle the predefined date style that date objects will be serialized/deserialized
-   * to/from
+   *     to/from
    * @param timeStyle the predefined style for the time portion of the date objects
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
+   * @throws IllegalArgumentException if the style values are invalid
    * @since 1.2
    */
   public GsonBuilder setDateFormat(int dateStyle, int timeStyle) {
-    this.dateStyle = dateStyle;
-    this.timeStyle = timeStyle;
+    this.dateStyle = checkDateFormatStyle(dateStyle);
+    this.timeStyle = checkDateFormatStyle(timeStyle);
     this.datePattern = null;
     return this;
   }
 
+  private static int checkDateFormatStyle(int style) {
+    // Valid DateFormat styles are: 0, 1, 2, 3 (FULL, LONG, MEDIUM, SHORT)
+    if (style < 0 || style > 3) {
+      throw new IllegalArgumentException("Invalid style: " + style);
+    }
+    return style;
+  }
+
   /**
    * Configures Gson for custom serialization or deserialization. This method combines the
    * registration of an {@link TypeAdapter}, {@link InstanceCreator}, {@link JsonSerializer}, and a
@@ -645,25 +674,36 @@ public final class GsonBuilder {
    *
    * <p>This registers the type specified and no other types: you must manually register related
    * types! For example, applications registering {@code boolean.class} should also register {@code
-   * Boolean.class}.
+   * Boolean.class}. And when registering an adapter for a class which has subclasses, you might
+   * also want to register the adapter for subclasses, or use {@link
+   * #registerTypeHierarchyAdapter(Class, Object)} instead.
    *
-   * <p>{@link JsonSerializer} and {@link JsonDeserializer} are made "{@code null}-safe". This
-   * means when trying to serialize {@code null}, Gson will write a JSON {@code null} and the
-   * serializer is not called. Similarly when deserializing a JSON {@code null}, Gson will emit
-   * {@code null} without calling the deserializer. If it is desired to handle {@code null} values,
-   * a {@link TypeAdapter} should be used instead.
+   * <p>{@link JsonSerializer} and {@link JsonDeserializer} are made "{@code null}-safe". This means
+   * when trying to serialize {@code null}, Gson will write a JSON {@code null} and the serializer
+   * is not called. Similarly when deserializing a JSON {@code null}, Gson will emit {@code null}
+   * without calling the deserializer. If it is desired to handle {@code null} values, a {@link
+   * TypeAdapter} should be used instead.
    *
    * @param type the type definition for the type adapter being registered
-   * @param typeAdapter This object must implement at least one of the {@link TypeAdapter},
-   * {@link InstanceCreator}, {@link JsonSerializer}, and a {@link JsonDeserializer} interfaces.
+   * @param typeAdapter This object must implement at least one of the {@link TypeAdapter}, {@link
+   *     InstanceCreator}, {@link JsonSerializer}, and a {@link JsonDeserializer} interfaces.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
+   * @throws IllegalArgumentException if the type adapter being registered is for {@code Object}
+   *     class or {@link JsonElement} or any of its subclasses
+   * @see #registerTypeHierarchyAdapter(Class, Object)
    */
   public GsonBuilder registerTypeAdapter(Type type, Object typeAdapter) {
     Objects.requireNonNull(type);
-    $Gson$Preconditions.checkArgument(typeAdapter instanceof JsonSerializer<?>
-        || typeAdapter instanceof JsonDeserializer<?>
-        || typeAdapter instanceof InstanceCreator<?>
-        || typeAdapter instanceof TypeAdapter<?>);
+    $Gson$Preconditions.checkArgument(
+        typeAdapter instanceof JsonSerializer<?>
+            || typeAdapter instanceof JsonDeserializer<?>
+            || typeAdapter instanceof InstanceCreator<?>
+            || typeAdapter instanceof TypeAdapter<?>);
+
+    if (isTypeObjectOrJsonElement(type)) {
+      throw new IllegalArgumentException("Cannot override built-in adapter for " + type);
+    }
+
     if (typeAdapter instanceof InstanceCreator<?>) {
       instanceCreators.put(type, (InstanceCreator<?>) typeAdapter);
     }
@@ -673,21 +713,27 @@ public final class GsonBuilder {
     }
     if (typeAdapter instanceof TypeAdapter<?>) {
       @SuppressWarnings({"unchecked", "rawtypes"})
-      TypeAdapterFactory factory = TypeAdapters.newFactory(TypeToken.get(type), (TypeAdapter)typeAdapter);
+      TypeAdapterFactory factory =
+          TypeAdapters.newFactory(TypeToken.get(type), (TypeAdapter) typeAdapter);
       factories.add(factory);
     }
     return this;
   }
 
+  private static boolean isTypeObjectOrJsonElement(Type type) {
+    return type instanceof Class
+        && (type == Object.class || JsonElement.class.isAssignableFrom((Class<?>) type));
+  }
+
   /**
-   * Register a factory for type adapters. Registering a factory is useful when the type
-   * adapter needs to be configured based on the type of the field being processed. Gson
-   * is designed to handle a large number of factories, so you should consider registering
-   * them to be at par with registering an individual type adapter.
+   * Registers a factory for type adapters. Registering a factory is useful when the type adapter
+   * needs to be configured based on the type of the field being processed. Gson is designed to
+   * handle a large number of factories, so you should consider registering them to be at par with
+   * registering an individual type adapter.
    *
-   * <p>The created Gson instance might only use the factory once to create an adapter for
-   * a specific type and cache the result. It is not guaranteed that the factory will be used
-   * again every time the type is serialized or deserialized.
+   * <p>The created Gson instance might only use the factory once to create an adapter for a
+   * specific type and cache the result. It is not guaranteed that the factory will be used again
+   * every time the type is serialized or deserialized.
    *
    * @since 2.1
    */
@@ -699,29 +745,38 @@ public final class GsonBuilder {
 
   /**
    * Configures Gson for custom serialization or deserialization for an inheritance type hierarchy.
-   * This method combines the registration of a {@link TypeAdapter}, {@link JsonSerializer} and
-   * a {@link JsonDeserializer}. If a type adapter was previously registered for the specified
-   * type hierarchy, it is overridden. If a type adapter is registered for a specific type in
-   * the type hierarchy, it will be invoked instead of the one registered for the type hierarchy.
+   * This method combines the registration of a {@link TypeAdapter}, {@link JsonSerializer} and a
+   * {@link JsonDeserializer}. If a type adapter was previously registered for the specified type
+   * hierarchy, it is overridden. If a type adapter is registered for a specific type in the type
+   * hierarchy, it will be invoked instead of the one registered for the type hierarchy.
    *
    * @param baseType the class definition for the type adapter being registered for the base class
-   *        or interface
-   * @param typeAdapter This object must implement at least one of {@link TypeAdapter},
-   *        {@link JsonSerializer} or {@link JsonDeserializer} interfaces.
+   *     or interface
+   * @param typeAdapter This object must implement at least one of {@link TypeAdapter}, {@link
+   *     JsonSerializer} or {@link JsonDeserializer} interfaces.
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
+   * @throws IllegalArgumentException if the type adapter being registered is for {@link
+   *     JsonElement} or any of its subclasses
    * @since 1.7
    */
   public GsonBuilder registerTypeHierarchyAdapter(Class<?> baseType, Object typeAdapter) {
     Objects.requireNonNull(baseType);
-    $Gson$Preconditions.checkArgument(typeAdapter instanceof JsonSerializer<?>
-        || typeAdapter instanceof JsonDeserializer<?>
-        || typeAdapter instanceof TypeAdapter<?>);
+    $Gson$Preconditions.checkArgument(
+        typeAdapter instanceof JsonSerializer<?>
+            || typeAdapter instanceof JsonDeserializer<?>
+            || typeAdapter instanceof TypeAdapter<?>);
+
+    if (JsonElement.class.isAssignableFrom(baseType)) {
+      throw new IllegalArgumentException("Cannot override built-in adapter for " + baseType);
+    }
+
     if (typeAdapter instanceof JsonDeserializer || typeAdapter instanceof JsonSerializer) {
       hierarchyFactories.add(TreeTypeAdapter.newTypeHierarchyFactory(baseType, typeAdapter));
     }
     if (typeAdapter instanceof TypeAdapter<?>) {
       @SuppressWarnings({"unchecked", "rawtypes"})
-      TypeAdapterFactory factory = TypeAdapters.newTypeHierarchyFactory(baseType, (TypeAdapter)typeAdapter);
+      TypeAdapterFactory factory =
+          TypeAdapters.newTypeHierarchyFactory(baseType, (TypeAdapter) typeAdapter);
       factories.add(factory);
     }
     return this;
@@ -729,20 +784,19 @@ public final class GsonBuilder {
 
   /**
    * Section 6 of <a href="https://www.ietf.org/rfc/rfc8259.txt">JSON specification</a> disallows
-   * special double values (NaN, Infinity, -Infinity). However,
-   * <a href="http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf">Javascript
+   * special double values (NaN, Infinity, -Infinity). However, <a
+   * href="http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf">Javascript
    * specification</a> (see section 4.3.20, 4.3.22, 4.3.23) allows these values as valid Javascript
    * values. Moreover, most JavaScript engines will accept these special values in JSON without
    * problem. So, at a practical level, it makes sense to accept these values as valid JSON even
    * though JSON specification disallows them.
    *
    * <p>Gson always accepts these special values during deserialization. However, it outputs
-   * strictly compliant JSON. Hence, if it encounters a float value {@link Float#NaN},
-   * {@link Float#POSITIVE_INFINITY}, {@link Float#NEGATIVE_INFINITY}, or a double value
-   * {@link Double#NaN}, {@link Double#POSITIVE_INFINITY}, {@link Double#NEGATIVE_INFINITY}, it
-   * will throw an {@link IllegalArgumentException}. This method provides a way to override the
-   * default behavior when you know that the JSON receiver will be able to handle these special
-   * values.
+   * strictly compliant JSON. Hence, if it encounters a float value {@link Float#NaN}, {@link
+   * Float#POSITIVE_INFINITY}, {@link Float#NEGATIVE_INFINITY}, or a double value {@link
+   * Double#NaN}, {@link Double#POSITIVE_INFINITY}, {@link Double#NEGATIVE_INFINITY}, it will throw
+   * an {@link IllegalArgumentException}. This method provides a way to override the default
+   * behavior when you know that the JSON receiver will be able to handle these special values.
    *
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
    * @since 1.3
@@ -755,15 +809,14 @@ public final class GsonBuilder {
   /**
    * Disables usage of JDK's {@code sun.misc.Unsafe}.
    *
-   * <p>By default Gson uses {@code Unsafe} to create instances of classes which don't have
-   * a no-args constructor. However, {@code Unsafe} might not be available for all Java
-   * runtimes. For example Android does not provide {@code Unsafe}, or only with limited
-   * functionality. Additionally {@code Unsafe} creates instances without executing any
-   * constructor or initializer block, or performing initialization of field values. This can
-   * lead to surprising and difficult to debug errors.
-   * Therefore, to get reliable behavior regardless of which runtime is used, and to detect
-   * classes which cannot be deserialized in an early stage of development, this method allows
-   * disabling usage of {@code Unsafe}.
+   * <p>By default Gson uses {@code Unsafe} to create instances of classes which don't have a
+   * no-args constructor. However, {@code Unsafe} might not be available for all Java runtimes. For
+   * example Android does not provide {@code Unsafe}, or only with limited functionality.
+   * Additionally {@code Unsafe} creates instances without executing any constructor or initializer
+   * block, or performing initialization of field values. This can lead to surprising and difficult
+   * to debug errors. Therefore, to get reliable behavior regardless of which runtime is used, and
+   * to detect classes which cannot be deserialized in an early stage of development, this method
+   * allows disabling usage of {@code Unsafe}.
    *
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
    * @since 2.9.0
@@ -774,20 +827,20 @@ public final class GsonBuilder {
   }
 
   /**
-   * Adds a reflection access filter. A reflection access filter prevents Gson from using
-   * reflection for the serialization and deserialization of certain classes. The logic in
-   * the filter specifies which classes those are.
+   * Adds a reflection access filter. A reflection access filter prevents Gson from using reflection
+   * for the serialization and deserialization of certain classes. The logic in the filter specifies
+   * which classes those are.
    *
-   * <p>Filters will be invoked in reverse registration order, that is, the most recently
-   * added filter will be invoked first.
+   * <p>Filters will be invoked in reverse registration order, that is, the most recently added
+   * filter will be invoked first.
    *
-   * <p>By default Gson has no filters configured and will try to use reflection for
-   * all classes for which no {@link TypeAdapter} has been registered, and for which no
-   * built-in Gson {@code TypeAdapter} exists.
+   * <p>By default Gson has no filters configured and will try to use reflection for all classes for
+   * which no {@link TypeAdapter} has been registered, and for which no built-in Gson {@code
+   * TypeAdapter} exists.
    *
-   * <p>The created Gson instance might only use an access filter once for a class or its
-   * members and cache the result. It is not guaranteed that the filter will be used again
-   * every time a class or its members are accessed during serialization or deserialization.
+   * <p>The created Gson instance might only use an access filter once for a class or its members
+   * and cache the result. It is not guaranteed that the filter will be used again every time a
+   * class or its members are accessed during serialization or deserialization.
    *
    * @param filter filter to add
    * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
@@ -806,7 +859,8 @@ public final class GsonBuilder {
    * @return an instance of Gson configured with the options currently set in this builder
    */
   public Gson create() {
-    List<TypeAdapterFactory> factories = new ArrayList<>(this.factories.size() + this.hierarchyFactories.size() + 3);
+    List<TypeAdapterFactory> factories =
+        new ArrayList<>(this.factories.size() + this.hierarchyFactories.size() + 3);
     factories.addAll(this.factories);
     Collections.reverse(factories);
 
@@ -816,17 +870,33 @@ public final class GsonBuilder {
 
     addTypeAdaptersForDate(datePattern, dateStyle, timeStyle, factories);
 
-    return new Gson(excluder, fieldNamingPolicy, new HashMap<>(instanceCreators),
-        serializeNulls, complexMapKeySerialization, duplicateMapKeyDeserialization,
-        generateNonExecutableJson, escapeHtmlChars, formattingStyle, strictness, omitQuotes,
-        serializeSpecialFloatingPointValues, useJdkUnsafe, longSerializationPolicy,
-        datePattern, dateStyle, timeStyle, new ArrayList<>(this.factories),
-        new ArrayList<>(this.hierarchyFactories), factories,
-        objectToNumberStrategy, numberToNumberStrategy, new ArrayList<>(reflectionFilters));
+    return new Gson(
+        excluder,
+        fieldNamingPolicy,
+        new HashMap<>(instanceCreators),
+        serializeNulls,
+        complexMapKeySerialization,
+        duplicateMapKeyDeserialization,
+        generateNonExecutableJson,
+        escapeHtmlChars,
+        formattingStyle,
+        strictness, omitQuotes,
+        serializeSpecialFloatingPointValues,
+        useJdkUnsafe,
+        longSerializationPolicy,
+        datePattern,
+        dateStyle,
+        timeStyle,
+        new ArrayList<>(this.factories),
+        new ArrayList<>(this.hierarchyFactories),
+        factories,
+        objectToNumberStrategy,
+        numberToNumberStrategy,
+        new ArrayList<>(reflectionFilters));
   }
 
-  private void addTypeAdaptersForDate(String datePattern, int dateStyle, int timeStyle,
-      List<TypeAdapterFactory> factories) {
+  private static void addTypeAdaptersForDate(
+      String datePattern, int dateStyle, int timeStyle, List<TypeAdapterFactory> factories) {
     TypeAdapterFactory dateAdapterFactory;
     boolean sqlTypesSupported = SqlTypesSupport.SUPPORTS_SQL_TYPES;
     TypeAdapterFactory sqlTimestampAdapterFactory = null;
@@ -836,15 +906,19 @@ public final class GsonBuilder {
       dateAdapterFactory = DefaultDateTypeAdapter.DateType.DATE.createAdapterFactory(datePattern);
 
       if (sqlTypesSupported) {
-        sqlTimestampAdapterFactory = SqlTypesSupport.TIMESTAMP_DATE_TYPE.createAdapterFactory(datePattern);
+        sqlTimestampAdapterFactory =
+            SqlTypesSupport.TIMESTAMP_DATE_TYPE.createAdapterFactory(datePattern);
         sqlDateAdapterFactory = SqlTypesSupport.DATE_DATE_TYPE.createAdapterFactory(datePattern);
       }
-    } else if (dateStyle != DateFormat.DEFAULT && timeStyle != DateFormat.DEFAULT) {
-      dateAdapterFactory = DefaultDateTypeAdapter.DateType.DATE.createAdapterFactory(dateStyle, timeStyle);
+    } else if (dateStyle != DateFormat.DEFAULT || timeStyle != DateFormat.DEFAULT) {
+      dateAdapterFactory =
+          DefaultDateTypeAdapter.DateType.DATE.createAdapterFactory(dateStyle, timeStyle);
 
       if (sqlTypesSupported) {
-        sqlTimestampAdapterFactory = SqlTypesSupport.TIMESTAMP_DATE_TYPE.createAdapterFactory(dateStyle, timeStyle);
-        sqlDateAdapterFactory = SqlTypesSupport.DATE_DATE_TYPE.createAdapterFactory(dateStyle, timeStyle);
+        sqlTimestampAdapterFactory =
+            SqlTypesSupport.TIMESTAMP_DATE_TYPE.createAdapterFactory(dateStyle, timeStyle);
+        sqlDateAdapterFactory =
+            SqlTypesSupport.DATE_DATE_TYPE.createAdapterFactory(dateStyle, timeStyle);
       }
     } else {
       return;

gson/src/main/java/com/google/gson/InstanceCreator.java

@@ -20,14 +20,15 @@ import java.lang.reflect.Type;
 
 /**
  * This interface is implemented to create instances of a class that does not define a no-args
- * constructor. If you can modify the class, you should instead add a private, or public
- * no-args constructor. However, that is not possible for library classes, such as JDK classes, or
- * a third-party library that you do not have source-code of. In such cases, you should define an
+ * constructor. If you can modify the class, you should instead add a private, or public no-args
+ * constructor. However, that is not possible for library classes, such as JDK classes, or a
+ * third-party library that you do not have source-code of. In such cases, you should define an
  * instance creator for the class. Implementations of this interface should be registered with
  * {@link GsonBuilder#registerTypeAdapter(Type, Object)} method before Gson will be able to use
  * them.
- * <p>Let us look at an example where defining an InstanceCreator might be useful. The
- * {@code Id} class defined below does not have a default no-args constructor.</p>
+ *
+ * <p>Let us look at an example where defining an InstanceCreator might be useful. The {@code Id}
+ * class defined below does not have a default no-args constructor.
  *
  * <pre>
  * public class Id&lt;T&gt; {
@@ -42,7 +43,7 @@ import java.lang.reflect.Type;
  *
  * <p>If Gson encounters an object of type {@code Id} during deserialization, it will throw an
  * exception. The easiest way to solve this problem will be to add a (public or private) no-args
- * constructor as follows:</p>
+ * constructor as follows:
  *
  * <pre>
  * private Id() {
@@ -51,8 +52,8 @@ import java.lang.reflect.Type;
  * </pre>
  *
  * <p>However, let us assume that the developer does not have access to the source-code of the
- * {@code Id} class, or does not want to define a no-args constructor for it. The developer
- * can solve this problem by defining an {@code InstanceCreator} for {@code Id}:</p>
+ * {@code Id} class, or does not want to define a no-args constructor for it. The developer can
+ * solve this problem by defining an {@code InstanceCreator} for {@code Id}:
  *
  * <pre>
  * class IdInstanceCreator implements InstanceCreator&lt;Id&gt; {
@@ -64,17 +65,15 @@ import java.lang.reflect.Type;
  *
  * <p>Note that it does not matter what the fields of the created instance contain since Gson will
  * overwrite them with the deserialized values specified in JSON. You should also ensure that a
- * <i>new</i> object is returned, not a common object since its fields will be overwritten.
- * The developer will need to register {@code IdInstanceCreator} with Gson as follows:</p>
+ * <i>new</i> object is returned, not a common object since its fields will be overwritten. The
+ * developer will need to register {@code IdInstanceCreator} with Gson as follows:
  *
  * <pre>
  * Gson gson = new GsonBuilder().registerTypeAdapter(Id.class, new IdInstanceCreator()).create();
  * </pre>
  *
  * @param <T> the type of object that will be created by this implementation.
- *
  * @see GsonBuilder#registerTypeAdapter(Type, Object)
- *
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
@@ -82,10 +81,10 @@ public interface InstanceCreator<T> {
 
   /**
    * Gson invokes this call-back method during deserialization to create an instance of the
-   * specified type. The fields of the returned instance are overwritten with the data present
-   * in the JSON. Since the prior contents of the object are destroyed and overwritten, do not
-   * return an instance that is useful elsewhere. In particular, do not return a common instance,
-   * always use {@code new} to create a new instance.
+   * specified type. The fields of the returned instance are overwritten with the data present in
+   * the JSON. Since the prior contents of the object are destroyed and overwritten, do not return
+   * an instance that is useful elsewhere. In particular, do not return a common instance, always
+   * use {@code new} to create a new instance.
    *
    * @param type the parameterized T represented as a {@link Type}.
    * @return a default object instance of type T.

gson/src/main/java/com/google/gson/JsonArray.java

@@ -38,9 +38,7 @@ import java.util.List;
 public final class JsonArray extends JsonElement implements Iterable<JsonElement> {
   private final ArrayList<JsonElement> elements;
 
-  /**
-   * Creates an empty JsonArray.
-   */
+  /** Creates an empty JsonArray. */
   @SuppressWarnings("deprecation") // superclass constructor
   public JsonArray() {
     elements = new ArrayList<>();
@@ -50,8 +48,7 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
    * Creates an empty JsonArray with the desired initial capacity.
    *
    * @param capacity initial capacity.
-   * @throws IllegalArgumentException if the {@code capacity} is
-   *   negative
+   * @throws IllegalArgumentException if the {@code capacity} is negative
    * @since 2.8.1
    */
   @SuppressWarnings("deprecation") // superclass constructor
@@ -150,8 +147,8 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Removes the first occurrence of the specified element from this array, if it is present.
-   * If the array does not contain the element, it is unchanged.
+   * Removes the first occurrence of the specified element from this array, if it is present. If the
+   * array does not contain the element, it is unchanged.
    *
    * @param element element to be removed from this array, if present
    * @return true if this array contained the specified element, false otherwise
@@ -162,9 +159,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Removes the element at the specified position in this array. Shifts any subsequent elements
-   * to the left (subtracts one from their indices). Returns the element that was removed from
-   * the array.
+   * Removes the element at the specified position in this array. Shifts any subsequent elements to
+   * the left (subtracts one from their indices). Returns the element that was removed from the
+   * array.
    *
    * @param index index the index of the element to be removed
    * @return the element previously at the specified position
@@ -221,8 +218,8 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
    *
    * @param i the index of the element that is being sought.
    * @return the element present at the i-th index.
-   * @throws IndexOutOfBoundsException if i is negative or greater than or equal to the
-   * {@link #size()} of the array.
+   * @throws IndexOutOfBoundsException if {@code i} is negative or greater than or equal to the
+   *     {@link #size()} of the array.
    */
   public JsonElement get(int i) {
     return elements.get(i);
@@ -237,9 +234,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a {@link Number} if it contains a single element.
-   * This method calls {@link JsonElement#getAsNumber()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a {@link Number} if it contains a single element. This
+   * method calls {@link JsonElement#getAsNumber()} on the element, therefore any of the exceptions
+   * declared by that method can occur.
    *
    * @return this element as a number if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -250,9 +247,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a {@link String} if it contains a single element.
-   * This method calls {@link JsonElement#getAsString()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a {@link String} if it contains a single element. This
+   * method calls {@link JsonElement#getAsString()} on the element, therefore any of the exceptions
+   * declared by that method can occur.
    *
    * @return this element as a String if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -263,9 +260,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a double if it contains a single element.
-   * This method calls {@link JsonElement#getAsDouble()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a double if it contains a single element. This method
+   * calls {@link JsonElement#getAsDouble()} on the element, therefore any of the exceptions
+   * declared by that method can occur.
    *
    * @return this element as a double if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -277,8 +274,8 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
 
   /**
    * Convenience method to get this array as a {@link BigDecimal} if it contains a single element.
-   * This method calls {@link JsonElement#getAsBigDecimal()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * This method calls {@link JsonElement#getAsBigDecimal()} on the element, therefore any of the
+   * exceptions declared by that method can occur.
    *
    * @return this element as a {@link BigDecimal} if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -291,8 +288,8 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
 
   /**
    * Convenience method to get this array as a {@link BigInteger} if it contains a single element.
-   * This method calls {@link JsonElement#getAsBigInteger()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * This method calls {@link JsonElement#getAsBigInteger()} on the element, therefore any of the
+   * exceptions declared by that method can occur.
    *
    * @return this element as a {@link BigInteger} if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -304,9 +301,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a float if it contains a single element.
-   * This method calls {@link JsonElement#getAsFloat()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a float if it contains a single element. This method
+   * calls {@link JsonElement#getAsFloat()} on the element, therefore any of the exceptions declared
+   * by that method can occur.
    *
    * @return this element as a float if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -317,9 +314,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a long if it contains a single element.
-   * This method calls {@link JsonElement#getAsLong()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a long if it contains a single element. This method
+   * calls {@link JsonElement#getAsLong()} on the element, therefore any of the exceptions declared
+   * by that method can occur.
    *
    * @return this element as a long if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -330,9 +327,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as an integer if it contains a single element.
-   * This method calls {@link JsonElement#getAsInt()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as an integer if it contains a single element. This method
+   * calls {@link JsonElement#getAsInt()} on the element, therefore any of the exceptions declared
+   * by that method can occur.
    *
    * @return this element as an integer if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -343,9 +340,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a primitive byte if it contains a single element.
-   * This method calls {@link JsonElement#getAsByte()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a primitive byte if it contains a single element. This
+   * method calls {@link JsonElement#getAsByte()} on the element, therefore any of the exceptions
+   * declared by that method can occur.
    *
    * @return this element as a primitive byte if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -356,14 +353,14 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a character if it contains a single element.
-   * This method calls {@link JsonElement#getAsCharacter()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a character if it contains a single element. This
+   * method calls {@link JsonElement#getAsCharacter()} on the element, therefore any of the
+   * exceptions declared by that method can occur.
    *
    * @return this element as a primitive short if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
    * @deprecated This method is misleading, as it does not get this element as a char but rather as
-   * a string's first character.
+   *     a string's first character.
    */
   @Deprecated
   @Override
@@ -372,9 +369,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a primitive short if it contains a single element.
-   * This method calls {@link JsonElement#getAsShort()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a primitive short if it contains a single element. This
+   * method calls {@link JsonElement#getAsShort()} on the element, therefore any of the exceptions
+   * declared by that method can occur.
    *
    * @return this element as a primitive short if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -385,9 +382,9 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Convenience method to get this array as a boolean if it contains a single element.
-   * This method calls {@link JsonElement#getAsBoolean()} on the element, therefore any
-   * of the exceptions declared by that method can occur.
+   * Convenience method to get this array as a boolean if it contains a single element. This method
+   * calls {@link JsonElement#getAsBoolean()} on the element, therefore any of the exceptions
+   * declared by that method can occur.
    *
    * @return this element as a boolean if it is single element array.
    * @throws IllegalStateException if the array is empty or has more than one element.
@@ -398,12 +395,12 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Returns a mutable {@link List} view of this {@code JsonArray}. Changes to the {@code List}
-   * are visible in this {@code JsonArray} and the other way around.
+   * Returns a mutable {@link List} view of this {@code JsonArray}. Changes to the {@code List} are
+   * visible in this {@code JsonArray} and the other way around.
    *
-   * <p>The {@code List} does not permit {@code null} elements. Unlike {@code JsonArray}'s
-   * {@code null} handling, a {@link NullPointerException} is thrown when trying to add {@code null}.
-   * Use {@link JsonNull} for JSON null values.
+   * <p>The {@code List} does not permit {@code null} elements. Unlike {@code JsonArray}'s {@code
+   * null} handling, a {@link NullPointerException} is thrown when trying to add {@code null}. Use
+   * {@link JsonNull} for JSON null values.
    *
    * @return mutable {@code List} view
    * @since 2.10
@@ -413,9 +410,8 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Returns whether the other object is equal to this. This method only considers
-   * the other object to be equal if it is an instance of {@code JsonArray} and has
-   * equal elements in the same order.
+   * Returns whether the other object is equal to this. This method only considers the other object
+   * to be equal if it is an instance of {@code JsonArray} and has equal elements in the same order.
    */
   @Override
   public boolean equals(Object o) {
@@ -423,8 +419,8 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   /**
-   * Returns the hash code of this array. This method calculates the hash code based
-   * on the elements of this array.
+   * Returns the hash code of this array. This method calculates the hash code based on the elements
+   * of this array.
    */
   @Override
   public int hashCode() {

gson/src/main/java/com/google/gson/JsonDeserializationContext.java

@@ -20,8 +20,7 @@ import java.lang.reflect.Type;
 
 /**
  * Context for deserialization that is passed to a custom deserializer during invocation of its
- * {@link JsonDeserializer#deserialize(JsonElement, Type, JsonDeserializationContext)}
- * method.
+ * {@link JsonDeserializer#deserialize(JsonElement, Type, JsonDeserializationContext)} method.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -29,10 +28,10 @@ import java.lang.reflect.Type;
 public interface JsonDeserializationContext {
 
   /**
-   * Invokes default deserialization on the specified object. It should never be invoked on
-   * the element received as a parameter of the
-   * {@link JsonDeserializer#deserialize(JsonElement, Type, JsonDeserializationContext)} method. Doing
-   * so will result in an infinite loop since Gson will in-turn call the custom deserializer again.
+   * Invokes default deserialization on the specified object. It should never be invoked on the
+   * element received as a parameter of the {@link JsonDeserializer#deserialize(JsonElement, Type,
+   * JsonDeserializationContext)} method. Doing so will result in an infinite loop since Gson will
+   * in-turn call the custom deserializer again.
    *
    * @param json the parse tree.
    * @param typeOfT type of the expected return value.
@@ -42,4 +41,4 @@ public interface JsonDeserializationContext {
    */
   @SuppressWarnings("TypeParameterUnusedInFormals")
   public <T> T deserialize(JsonElement json, Type typeOfT) throws JsonParseException;
-}
+}

gson/src/main/java/com/google/gson/JsonDeserializer.java

@@ -19,13 +19,12 @@ package com.google.gson;
 import java.lang.reflect.Type;
 
 /**
- * <p>Interface representing a custom deserializer for JSON. You should write a custom
- * deserializer, if you are not happy with the default deserialization done by Gson. You will
- * also need to register this deserializer through
- * {@link GsonBuilder#registerTypeAdapter(Type, Object)}.</p>
+ * Interface representing a custom deserializer for JSON. You should write a custom deserializer, if
+ * you are not happy with the default deserialization done by Gson. You will also need to register
+ * this deserializer through {@link GsonBuilder#registerTypeAdapter(Type, Object)}.
  *
  * <p>Let us look at example where defining a deserializer will be useful. The {@code Id} class
- * defined below has two fields: {@code clazz} and {@code value}.</p>
+ * defined below has two fields: {@code clazz} and {@code value}.
  *
  * <pre>
  * public class Id&lt;T&gt; {
@@ -41,11 +40,11 @@ import java.lang.reflect.Type;
  * }
  * </pre>
  *
- * <p>The default deserialization of {@code Id(com.foo.MyObject.class, 20L)} will require the
- * JSON string to be <code>{"clazz":"com.foo.MyObject","value":20}</code>. Suppose, you already know
- * the type of the field that the {@code Id} will be deserialized into, and hence just want to
+ * <p>The default deserialization of {@code Id(com.foo.MyObject.class, 20L)} will require the JSON
+ * string to be <code>{"clazz":"com.foo.MyObject","value":20}</code>. Suppose, you already know the
+ * type of the field that the {@code Id} will be deserialized into, and hence just want to
  * deserialize it from a JSON string {@code 20}. You can achieve that by writing a custom
- * deserializer:</p>
+ * deserializer:
  *
  * <pre>
  * class IdDeserializer implements JsonDeserializer&lt;Id&gt; {
@@ -57,34 +56,34 @@ import java.lang.reflect.Type;
  * }
  * </pre>
  *
- * <p>You will also need to register {@code IdDeserializer} with Gson as follows:</p>
+ * <p>You will also need to register {@code IdDeserializer} with Gson as follows:
  *
  * <pre>
  * Gson gson = new GsonBuilder().registerTypeAdapter(Id.class, new IdDeserializer()).create();
  * </pre>
  *
- * <p>Deserializers should be stateless and thread-safe, otherwise the thread-safety
- * guarantees of {@link Gson} might not apply.
+ * <p>Deserializers should be stateless and thread-safe, otherwise the thread-safety guarantees of
+ * {@link Gson} might not apply.
  *
- * <p>New applications should prefer {@link TypeAdapter}, whose streaming API
- * is more efficient than this interface's tree API.
+ * <p>New applications should prefer {@link TypeAdapter}, whose streaming API is more efficient than
+ * this interface's tree API.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
- *
  * @param <T> type for which the deserializer is being registered. It is possible that a
- * deserializer may be asked to deserialize a specific generic type of the T.
+ *     deserializer may be asked to deserialize a specific generic type of the T.
  */
 public interface JsonDeserializer<T> {
 
   /**
    * Gson invokes this call-back method during deserialization when it encounters a field of the
    * specified type.
-   * <p>In the implementation of this call-back method, you should consider invoking
-   * {@link JsonDeserializationContext#deserialize(JsonElement, Type)} method to create objects
-   * for any non-trivial field of the returned object. However, you should never invoke it on the
-   * same type passing {@code json} since that will cause an infinite loop (Gson will call your
-   * call-back method again).
+   *
+   * <p>In the implementation of this call-back method, you should consider invoking {@link
+   * JsonDeserializationContext#deserialize(JsonElement, Type)} method to create objects for any
+   * non-trivial field of the returned object. However, you should never invoke it on the same type
+   * passing {@code json} since that will cause an infinite loop (Gson will call your call-back
+   * method again).
    *
    * @param json The Json data being deserialized
    * @param typeOfT The type of the Object to deserialize to

gson/src/main/java/com/google/gson/JsonElement.java

@@ -24,25 +24,24 @@ import java.math.BigDecimal;
 import java.math.BigInteger;
 
 /**
- * A class representing an element of JSON. It could either be a {@link JsonObject}, a
- * {@link JsonArray}, a {@link JsonPrimitive} or a {@link JsonNull}.
+ * A class representing an element of JSON. It could either be a {@link JsonObject}, a {@link
+ * JsonArray}, a {@link JsonPrimitive} or a {@link JsonNull}.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
 public abstract class JsonElement {
   /**
-   * @deprecated Creating custom {@code JsonElement} subclasses is highly discouraged
-   *   and can lead to undefined behavior.<br>
-   *   This constructor is only kept for backward compatibility.
+   * @deprecated Creating custom {@code JsonElement} subclasses is highly discouraged and can lead
+   *     to undefined behavior.<br>
+   *     This constructor is only kept for backward compatibility.
    */
   @Deprecated
-  public JsonElement() {
-  }
+  public JsonElement() {}
 
   /**
-   * Returns a deep copy of this element. Immutable elements like primitives
-   * and nulls are not copied.
+   * Returns a deep copy of this element. Immutable elements like primitives and nulls are not
+   * copied.
    *
    * @since 2.8.2
    */
@@ -102,10 +101,9 @@ public abstract class JsonElement {
   }
 
   /**
-   * Convenience method to get this element as a {@link JsonArray}. If this element is of some
-   * other type, an {@link IllegalStateException} will result. Hence it is best to use this method
-   * after ensuring that this element is of the desired type by calling {@link #isJsonArray()}
-   * first.
+   * Convenience method to get this element as a {@link JsonArray}. If this element is of some other
+   * type, an {@link IllegalStateException} will result. Hence it is best to use this method after
+   * ensuring that this element is of the desired type by calling {@link #isJsonArray()} first.
    *
    * @return this element as a {@link JsonArray}.
    * @throws IllegalStateException if this element is of another type.
@@ -134,10 +132,9 @@ public abstract class JsonElement {
   }
 
   /**
-   * Convenience method to get this element as a {@link JsonNull}. If this element is of some
-   * other type, an {@link IllegalStateException} will result. Hence it is best to use this method
-   * after ensuring that this element is of the desired type by calling {@link #isJsonNull()}
-   * first.
+   * Convenience method to get this element as a {@link JsonNull}. If this element is of some other
+   * type, an {@link IllegalStateException} will result. Hence it is best to use this method after
+   * ensuring that this element is of the desired type by calling {@link #isJsonNull()} first.
    *
    * @return this element as a {@link JsonNull}.
    * @throws IllegalStateException if this element is of another type.
@@ -154,9 +151,10 @@ public abstract class JsonElement {
    * Convenience method to get this element as a boolean value.
    *
    * @return this element as a primitive boolean value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public boolean getAsBoolean() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
@@ -166,10 +164,10 @@ public abstract class JsonElement {
    * Convenience method to get this element as a {@link Number}.
    *
    * @return this element as a {@link Number}.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray},
-   * or cannot be converted to a number.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}, or cannot be converted to a number.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public Number getAsNumber() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
@@ -179,9 +177,10 @@ public abstract class JsonElement {
    * Convenience method to get this element as a string value.
    *
    * @return this element as a string value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public String getAsString() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
@@ -191,10 +190,11 @@ public abstract class JsonElement {
    * Convenience method to get this element as a primitive double value.
    *
    * @return this element as a primitive double value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if the value contained is not a valid double.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public double getAsDouble() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
@@ -204,10 +204,11 @@ public abstract class JsonElement {
    * Convenience method to get this element as a primitive float value.
    *
    * @return this element as a primitive float value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if the value contained is not a valid float.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public float getAsFloat() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
@@ -217,10 +218,11 @@ public abstract class JsonElement {
    * Convenience method to get this element as a primitive long value.
    *
    * @return this element as a primitive long value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if the value contained is not a valid long.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public long getAsLong() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
@@ -230,10 +232,11 @@ public abstract class JsonElement {
    * Convenience method to get this element as a primitive integer value.
    *
    * @return this element as a primitive integer value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if the value contained is not a valid integer.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public int getAsInt() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
@@ -243,10 +246,11 @@ public abstract class JsonElement {
    * Convenience method to get this element as a primitive byte value.
    *
    * @return this element as a primitive byte value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if the value contained is not a valid byte.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    * @since 1.3
    */
   public byte getAsByte() {
@@ -257,13 +261,13 @@ public abstract class JsonElement {
    * Convenience method to get the first character of the string value of this element.
    *
    * @return the first character of the string value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray},
-   * or if its string value is empty.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}, or if its string value is empty.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    * @since 1.3
    * @deprecated This method is misleading, as it does not get this element as a char but rather as
-   * a string's first character.
+   *     a string's first character.
    */
   @Deprecated
   public char getAsCharacter() {
@@ -274,10 +278,11 @@ public abstract class JsonElement {
    * Convenience method to get this element as a {@link BigDecimal}.
    *
    * @return this element as a {@link BigDecimal}.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if this element is not a valid {@link BigDecimal}.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    * @since 1.2
    */
   public BigDecimal getAsBigDecimal() {
@@ -288,10 +293,11 @@ public abstract class JsonElement {
    * Convenience method to get this element as a {@link BigInteger}.
    *
    * @return this element as a {@link BigInteger}.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if this element is not a valid {@link BigInteger}.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    * @since 1.2
    */
   public BigInteger getAsBigInteger() {
@@ -302,24 +308,24 @@ public abstract class JsonElement {
    * Convenience method to get this element as a primitive short value.
    *
    * @return this element as a primitive short value.
-   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link JsonArray}.
+   * @throws UnsupportedOperationException if this element is not a {@link JsonPrimitive} or {@link
+   *     JsonArray}.
    * @throws NumberFormatException if the value contained is not a valid short.
    * @throws IllegalStateException if this element is of the type {@link JsonArray} but contains
-   * more than a single element.
+   *     more than a single element.
    */
   public short getAsShort() {
     throw new UnsupportedOperationException(getClass().getSimpleName());
   }
 
-  /**
-   * Returns a String representation of this element.
-   */
+  /** Returns a String representation of this element. */
   @Override
   public String toString() {
     try {
       StringWriter stringWriter = new StringWriter();
       JsonWriter jsonWriter = new JsonWriter(stringWriter);
-      // Make writer lenient because toString() must not fail, even if for example JsonPrimitive contains NaN
+      // Make writer lenient because toString() must not fail, even if for example JsonPrimitive
+      // contains NaN
       jsonWriter.setStrictness(Strictness.LENIENT);
       Streams.write(this, jsonWriter);
       return stringWriter.toString();

gson/src/main/java/com/google/gson/JsonIOException.java

@@ -16,9 +16,8 @@
 package com.google.gson;
 
 /**
- * This exception is raised when Gson was unable to read an input stream
- * or write to one.
- * 
+ * This exception is raised when Gson was unable to read an input stream or write to one.
+ *
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
@@ -34,8 +33,8 @@ public final class JsonIOException extends JsonParseException {
   }
 
   /**
-   * Creates exception with the specified cause. Consider using
-   * {@link #JsonIOException(String, Throwable)} instead if you can describe what happened.
+   * Creates exception with the specified cause. Consider using {@link #JsonIOException(String,
+   * Throwable)} instead if you can describe what happened.
    *
    * @param cause root exception that caused this exception to be thrown.
    */

gson/src/main/java/com/google/gson/JsonNull.java

@@ -1,69 +1,65 @@
-/*
- * Copyright (C) 2008 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.google.gson;
-
-/**
- * A class representing a JSON {@code null} value.
- *
- * @author Inderjeet Singh
- * @author Joel Leitch
- * @since 1.2
- */
-public final class JsonNull extends JsonElement {
-  /**
-   * Singleton for {@code JsonNull}.
-   *
-   * @since 1.8
-   */
-  public static final JsonNull INSTANCE = new JsonNull();
-
-  /**
-   * Creates a new {@code JsonNull} object.
-   *
-   * @deprecated Deprecated since Gson version 1.8, use {@link #INSTANCE} instead.
-   */
-  @Deprecated
-  public JsonNull() {
-    // Do nothing
-  }
-
-  /**
-   * Returns the same instance since it is an immutable value.
-   *
-   * @since 2.8.2
-   */
-  @Override
-  public JsonNull deepCopy() {
-    return INSTANCE;
-  }
-
-  /**
-   * All instances of {@code JsonNull} have the same hash code since they are indistinguishable.
-   */
-  @Override
-  public int hashCode() {
-    return JsonNull.class.hashCode();
-  }
-
-  /**
-   * All instances of {@code JsonNull} are considered equal.
-   */
-  @Override
-  public boolean equals(Object other) {
-    return other instanceof JsonNull;
-  }
-}
+/*
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.gson;
+
+/**
+ * A class representing a JSON {@code null} value.
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ * @since 1.2
+ */
+public final class JsonNull extends JsonElement {
+  /**
+   * Singleton for {@code JsonNull}.
+   *
+   * @since 1.8
+   */
+  public static final JsonNull INSTANCE = new JsonNull();
+
+  /**
+   * Creates a new {@code JsonNull} object.
+   *
+   * @deprecated Deprecated since Gson version 1.8, use {@link #INSTANCE} instead.
+   */
+  @Deprecated
+  public JsonNull() {
+    // Do nothing
+  }
+
+  /**
+   * Returns the same instance since it is an immutable value.
+   *
+   * @since 2.8.2
+   */
+  @Override
+  public JsonNull deepCopy() {
+    return INSTANCE;
+  }
+
+  /** All instances of {@code JsonNull} have the same hash code since they are indistinguishable. */
+  @Override
+  public int hashCode() {
+    return JsonNull.class.hashCode();
+  }
+
+  /** All instances of {@code JsonNull} are considered equal. */
+  @Override
+  public boolean equals(Object other) {
+    return other instanceof JsonNull;
+  }
+}

gson/src/main/java/com/google/gson/JsonObject.java

@@ -24,11 +24,11 @@ import java.util.Set;
  * A class representing an object type in Json. An object consists of name-value pairs where names
  * are strings, and values are any other type of {@link JsonElement}. This allows for a creating a
  * tree of JsonElements. The member elements of this object are maintained in order they were added.
- * This class does not support {@code null} values. If {@code null} is provided as value argument
- * to any of the methods, it is converted to a {@link JsonNull}.
+ * This class does not support {@code null} values. If {@code null} is provided as value argument to
+ * any of the methods, it is converted to a {@link JsonNull}.
  *
- * <p>{@code JsonObject} does not implement the {@link Map} interface, but a {@code Map} view
- * of it can be obtained with {@link #asMap()}.
+ * <p>{@code JsonObject} does not implement the {@link Map} interface, but a {@code Map} view of it
+ * can be obtained with {@link #asMap()}.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -36,12 +36,9 @@ import java.util.Set;
 public final class JsonObject extends JsonElement {
   private final LinkedTreeMap<String, JsonElement> members = new LinkedTreeMap<>(false);
 
-  /**
-   * Creates an empty JsonObject.
-   */
+  /** Creates an empty JsonObject. */
   @SuppressWarnings("deprecation") // superclass constructor
-  public JsonObject() {
-  }
+  public JsonObject() {}
 
   /**
    * Creates a deep copy of this element and all its children.
@@ -59,8 +56,8 @@ public final class JsonObject extends JsonElement {
 
   /**
    * Adds a member, which is a name-value pair, to self. The name must be a String, but the value
-   * can be an arbitrary {@link JsonElement}, thereby allowing you to build a full tree of JsonElements
-   * rooted at this node.
+   * can be an arbitrary {@link JsonElement}, thereby allowing you to build a full tree of
+   * JsonElements rooted at this node.
    *
    * @param property name of the member.
    * @param value the member object.
@@ -73,8 +70,8 @@ public final class JsonObject extends JsonElement {
    * Removes the {@code property} from this object.
    *
    * @param property name of the member that should be removed.
-   * @return the {@link JsonElement} object that is being removed, or {@code null} if no
-   *   member with this name exists.
+   * @return the {@link JsonElement} object that is being removed, or {@code null} if no member with
+   *     this name exists.
    * @since 1.3
    */
   public JsonElement remove(String property) {
@@ -82,8 +79,8 @@ public final class JsonObject extends JsonElement {
   }
 
   /**
-   * Convenience method to add a string member. The specified value is converted to a
-   * {@link JsonPrimitive} of String.
+   * Convenience method to add a string member. The specified value is converted to a {@link
+   * JsonPrimitive} of String.
    *
    * @param property name of the member.
    * @param value the string value associated with the member.
@@ -93,8 +90,8 @@ public final class JsonObject extends JsonElement {
   }
 
   /**
-   * Convenience method to add a number member. The specified value is converted to a
-   * {@link JsonPrimitive} of Number.
+   * Convenience method to add a number member. The specified value is converted to a {@link
+   * JsonPrimitive} of Number.
    *
    * @param property name of the member.
    * @param value the number value associated with the member.
@@ -104,8 +101,8 @@ public final class JsonObject extends JsonElement {
   }
 
   /**
-   * Convenience method to add a boolean member. The specified value is converted to a
-   * {@link JsonPrimitive} of Boolean.
+   * Convenience method to add a boolean member. The specified value is converted to a {@link
+   * JsonPrimitive} of Boolean.
    *
    * @param property name of the member.
    * @param value the boolean value associated with the member.
@@ -115,8 +112,8 @@ public final class JsonObject extends JsonElement {
   }
 
   /**
-   * Convenience method to add a char member. The specified value is converted to a
-   * {@link JsonPrimitive} of Character.
+   * Convenience method to add a char member. The specified value is converted to a {@link
+   * JsonPrimitive} of Character.
    *
    * @param property name of the member.
    * @param value the char value associated with the member.
@@ -190,7 +187,7 @@ public final class JsonObject extends JsonElement {
    *
    * @param memberName name of the member being requested.
    * @return the {@code JsonPrimitive} corresponding to the specified member, or {@code null} if no
-   *   member with this name exists.
+   *     member with this name exists.
    * @throws ClassCastException if the member is not of type {@code JsonPrimitive}.
    */
   public JsonPrimitive getAsJsonPrimitive(String memberName) {
@@ -202,7 +199,7 @@ public final class JsonObject extends JsonElement {
    *
    * @param memberName name of the member being requested.
    * @return the {@code JsonArray} corresponding to the specified member, or {@code null} if no
-   *   member with this name exists.
+   *     member with this name exists.
    * @throws ClassCastException if the member is not of type {@code JsonArray}.
    */
   public JsonArray getAsJsonArray(String memberName) {
@@ -214,7 +211,7 @@ public final class JsonObject extends JsonElement {
    *
    * @param memberName name of the member being requested.
    * @return the {@code JsonObject} corresponding to the specified member, or {@code null} if no
-   *   member with this name exists.
+   *     member with this name exists.
    * @throws ClassCastException if the member is not of type {@code JsonObject}.
    */
   public JsonObject getAsJsonObject(String memberName) {
@@ -222,12 +219,12 @@ public final class JsonObject extends JsonElement {
   }
 
   /**
-   * Returns a mutable {@link Map} view of this {@code JsonObject}. Changes to the {@code Map}
-   * are visible in this {@code JsonObject} and the other way around.
+   * Returns a mutable {@link Map} view of this {@code JsonObject}. Changes to the {@code Map} are
+   * visible in this {@code JsonObject} and the other way around.
    *
    * <p>The {@code Map} does not permit {@code null} keys or values. Unlike {@code JsonObject}'s
-   * {@code null} handling, a {@link NullPointerException} is thrown when trying to add {@code null}.
-   * Use {@link JsonNull} for JSON null values.
+   * {@code null} handling, a {@link NullPointerException} is thrown when trying to add {@code
+   * null}. Use {@link JsonNull} for JSON null values.
    *
    * @return mutable {@code Map} view
    * @since 2.10
@@ -238,19 +235,17 @@ public final class JsonObject extends JsonElement {
   }
 
   /**
-   * Returns whether the other object is equal to this. This method only considers
-   * the other object to be equal if it is an instance of {@code JsonObject} and has
-   * equal members, ignoring order.
+   * Returns whether the other object is equal to this. This method only considers the other object
+   * to be equal if it is an instance of {@code JsonObject} and has equal members, ignoring order.
    */
   @Override
   public boolean equals(Object o) {
-    return (o == this) || (o instanceof JsonObject
-        && ((JsonObject) o).members.equals(members));
+    return (o == this) || (o instanceof JsonObject && ((JsonObject) o).members.equals(members));
   }
 
   /**
-   * Returns the hash code of this object. This method calculates the hash code based
-   * on the members of this object, ignoring order.
+   * Returns the hash code of this object. This method calculates the hash code based on the members
+   * of this object, ignoring order.
    */
   @Override
   public int hashCode() {

gson/src/main/java/com/google/gson/JsonParseException.java

@@ -17,14 +17,14 @@
 package com.google.gson;
 
 /**
- * This exception is raised if there is a serious issue that occurs during parsing of a Json
- * string. One of the main usages for this class is for the Gson infrastructure. If the incoming
- * Json is bad/malicious, an instance of this exception is raised.
+ * This exception is raised if there is a serious issue that occurs during parsing of a Json string.
+ * One of the main usages for this class is for the Gson infrastructure. If the incoming Json is
+ * bad/malicious, an instance of this exception is raised.
  *
  * <p>This exception is a {@link RuntimeException} because it is exposed to the client. Using a
  * {@link RuntimeException} avoids bad coding practices on the client side where they catch the
  * exception and do nothing. It is often the case that you want to blow up if there is a parsing
- * error (i.e. often clients do not know how to recover from a {@link JsonParseException}.</p>
+ * error (i.e. often clients do not know how to recover from a {@link JsonParseException}.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -53,8 +53,8 @@ public class JsonParseException extends RuntimeException {
   }
 
   /**
-   * Creates exception with the specified cause. Consider using
-   * {@link #JsonParseException(String, Throwable)} instead if you can describe what happened.
+   * Creates exception with the specified cause. Consider using {@link #JsonParseException(String,
+   * Throwable)} instead if you can describe what happened.
    *
    * @param cause root exception that caused this exception to be thrown.
    */

gson/src/main/java/com/google/gson/JsonParser.java

@@ -1,129 +1,135 @@
-/*
- * Copyright (C) 2009 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.google.gson;
-
-import com.google.gson.internal.Streams;
-import com.google.gson.stream.JsonReader;
-import com.google.gson.stream.JsonToken;
-import com.google.gson.stream.MalformedJsonException;
-import java.io.IOException;
-import java.io.Reader;
-import java.io.StringReader;
-
-/**
- * A parser to parse JSON into a parse tree of {@link JsonElement}s.
- *
- * @author Inderjeet Singh
- * @author Joel Leitch
- * @since 1.3
- */
-public final class JsonParser {
-  /** @deprecated No need to instantiate this class, use the static methods instead. */
-  @Deprecated
-  public JsonParser() {}
-
-  /**
-   * Parses the specified JSON string into a parse tree.
-   * An exception is thrown if the JSON string has multiple top-level JSON elements,
-   * or if there is trailing data.
-   *
-   * <p>The JSON string is parsed in {@linkplain JsonReader#setStrictness(Strictness) lenient mode}.
-   *
-   * @param json JSON text
-   * @return a parse tree of {@link JsonElement}s corresponding to the specified JSON
-   * @throws JsonParseException if the specified text is not valid JSON
-   * @since 2.8.6
-   */
-  public static JsonElement parseString(String json) throws JsonSyntaxException {
-    return parseReader(new StringReader(json));
-  }
-
-  /**
-   * Parses the complete JSON string provided by the reader into a parse tree.
-   * An exception is thrown if the JSON string has multiple top-level JSON elements,
-   * or if there is trailing data.
-   *
-   * <p>The JSON data is parsed in {@linkplain JsonReader#setStrictness(Strictness) lenient mode}.
-   *
-   * @param reader JSON text
-   * @return a parse tree of {@link JsonElement}s corresponding to the specified JSON
-   * @throws JsonParseException if there is an IOException or if the specified
-   *     text is not valid JSON
-   * @since 2.8.6
-   */
-  public static JsonElement parseReader(Reader reader) throws JsonIOException, JsonSyntaxException {
-    try {
-      JsonReader jsonReader = new JsonReader(reader);
-      JsonElement element = parseReader(jsonReader);
-      if (!element.isJsonNull() && jsonReader.peek() != JsonToken.END_DOCUMENT) {
-        throw new JsonSyntaxException("Did not consume the entire document.");
-      }
-      return element;
-    } catch (MalformedJsonException e) {
-      throw new JsonSyntaxException(e);
-    } catch (IOException e) {
-      throw new JsonIOException(e);
-    } catch (NumberFormatException e) {
-      throw new JsonSyntaxException(e);
-    }
-  }
-
-  /**
-   * Returns the next value from the JSON stream as a parse tree.
-   * Unlike the other {@code parse} methods, no exception is thrown if the JSON data has
-   * multiple top-level JSON elements, or if there is trailing data.
-   *
-   * <p>The JSON data is parsed in {@linkplain JsonReader#setStrictness(Strictness) lenient mode},
-   * regardless of the strictness setting of the provided reader. The strictness setting
-   * of the reader is restored once this method returns.
-   *
-   * @throws JsonParseException if there is an IOException or if the specified
-   *     text is not valid JSON
-   * @since 2.8.6
-   */
-  public static JsonElement parseReader(JsonReader reader)
-      throws JsonIOException, JsonSyntaxException {
-    Strictness strictness = reader.getStrictness();
-    reader.setStrictness(Strictness.LENIENT);
-    try {
-      return Streams.parse(reader);
-    } catch (StackOverflowError e) {
-      throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
-    } catch (OutOfMemoryError e) {
-      throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
-    } finally {
-      reader.setStrictness(strictness);
-    }
-  }
-
-  /** @deprecated Use {@link JsonParser#parseString} */
-  @Deprecated
-  public JsonElement parse(String json) throws JsonSyntaxException {
-    return parseString(json);
-  }
-
-  /** @deprecated Use {@link JsonParser#parseReader(Reader)} */
-  @Deprecated
-  public JsonElement parse(Reader json) throws JsonIOException, JsonSyntaxException {
-    return parseReader(json);
-  }
-
-  /** @deprecated Use {@link JsonParser#parseReader(JsonReader)} */
-  @Deprecated
-  public JsonElement parse(JsonReader json) throws JsonIOException, JsonSyntaxException {
-    return parseReader(json);
-  }
-}
+/*
+ * Copyright (C) 2009 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.gson;
+
+import com.google.gson.internal.Streams;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.MalformedJsonException;
+import java.io.IOException;
+import java.io.Reader;
+import java.io.StringReader;
+
+/**
+ * A parser to parse JSON into a parse tree of {@link JsonElement}s.
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ * @since 1.3
+ */
+public final class JsonParser {
+  /**
+   * @deprecated No need to instantiate this class, use the static methods instead.
+   */
+  @Deprecated
+  public JsonParser() {}
+
+  /**
+   * Parses the specified JSON string into a parse tree. An exception is thrown if the JSON string
+   * has multiple top-level JSON elements, or if there is trailing data.
+   *
+   * <p>The JSON string is parsed in {@linkplain JsonReader#setStrictness(Strictness) lenient mode}.
+   *
+   * @param json JSON text
+   * @return a parse tree of {@link JsonElement}s corresponding to the specified JSON
+   * @throws JsonParseException if the specified text is not valid JSON
+   * @since 2.8.6
+   */
+  public static JsonElement parseString(String json) throws JsonSyntaxException {
+    return parseReader(new StringReader(json));
+  }
+
+  /**
+   * Parses the complete JSON string provided by the reader into a parse tree. An exception is
+   * thrown if the JSON string has multiple top-level JSON elements, or if there is trailing data.
+   *
+   * <p>The JSON data is parsed in {@linkplain JsonReader#setStrictness(Strictness) lenient mode}.
+   *
+   * @param reader JSON text
+   * @return a parse tree of {@link JsonElement}s corresponding to the specified JSON
+   * @throws JsonParseException if there is an IOException or if the specified text is not valid
+   *     JSON
+   * @since 2.8.6
+   */
+  public static JsonElement parseReader(Reader reader) throws JsonIOException, JsonSyntaxException {
+    try {
+      JsonReader jsonReader = new JsonReader(reader);
+      JsonElement element = parseReader(jsonReader);
+      if (!element.isJsonNull() && jsonReader.peek() != JsonToken.END_DOCUMENT) {
+        throw new JsonSyntaxException("Did not consume the entire document.");
+      }
+      return element;
+    } catch (MalformedJsonException e) {
+      throw new JsonSyntaxException(e);
+    } catch (IOException e) {
+      throw new JsonIOException(e);
+    } catch (NumberFormatException e) {
+      throw new JsonSyntaxException(e);
+    }
+  }
+
+  /**
+   * Returns the next value from the JSON stream as a parse tree. Unlike the other {@code parse}
+   * methods, no exception is thrown if the JSON data has multiple top-level JSON elements, or if
+   * there is trailing data.
+   *
+   * <p>The JSON data is parsed in {@linkplain JsonReader#setStrictness(Strictness) lenient mode},
+   * regardless of the strictness setting of the provided reader. The strictness setting of the
+   * reader is restored once this method returns.
+   *
+   * @throws JsonParseException if there is an IOException or if the specified text is not valid
+   *     JSON
+   * @since 2.8.6
+   */
+  public static JsonElement parseReader(JsonReader reader)
+      throws JsonIOException, JsonSyntaxException {
+    Strictness strictness = reader.getStrictness();
+    reader.setStrictness(Strictness.LENIENT);
+    try {
+      return Streams.parse(reader);
+    } catch (StackOverflowError e) {
+      throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
+    } catch (OutOfMemoryError e) {
+      throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
+    } finally {
+      reader.setStrictness(strictness);
+    }
+  }
+
+  /**
+   * @deprecated Use {@link JsonParser#parseString}
+   */
+  @Deprecated
+  public JsonElement parse(String json) throws JsonSyntaxException {
+    return parseString(json);
+  }
+
+  /**
+   * @deprecated Use {@link JsonParser#parseReader(Reader)}
+   */
+  @Deprecated
+  public JsonElement parse(Reader json) throws JsonIOException, JsonSyntaxException {
+    return parseReader(json);
+  }
+
+  /**
+   * @deprecated Use {@link JsonParser#parseReader(JsonReader)}
+   */
+  @Deprecated
+  public JsonElement parse(JsonReader json) throws JsonIOException, JsonSyntaxException {
+    return parseReader(json);
+  }
+}

gson/src/main/java/com/google/gson/JsonPrimitive.java

@@ -17,14 +17,14 @@
 package com.google.gson;
 
 import com.google.gson.internal.LazilyParsedNumber;
+import com.google.gson.internal.NumberLimits;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.util.Objects;
 
 /**
- * A class representing a JSON primitive value. A primitive value
- * is either a String, a Java primitive, or a Java primitive
- * wrapper type.
+ * A class representing a JSON primitive value. A primitive value is either a String, a Java
+ * primitive, or a Java primitive wrapper type.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -38,7 +38,10 @@ public final class JsonPrimitive extends JsonElement {
    *
    * @param bool the value to create the primitive with.
    */
-  @SuppressWarnings("deprecation") // superclass constructor
+  // "deprecation" suppression for superclass constructor
+  // "UnnecessaryBoxedVariable" Error Prone warning is correct since method does not accept
+  // null, but cannot be changed anymore since this is public API
+  @SuppressWarnings({"deprecation", "UnnecessaryBoxedVariable"})
   public JsonPrimitive(Boolean bool) {
     value = Objects.requireNonNull(bool);
   }
@@ -69,7 +72,10 @@ public final class JsonPrimitive extends JsonElement {
    *
    * @param c the value to create the primitive with.
    */
-  @SuppressWarnings("deprecation") // superclass constructor
+  // "deprecation" suppression for superclass constructor
+  // "UnnecessaryBoxedVariable" Error Prone warning is correct since method does not accept
+  // null, but cannot be changed anymore since this is public API
+  @SuppressWarnings({"deprecation", "UnnecessaryBoxedVariable"})
   public JsonPrimitive(Character c) {
     // convert characters to strings since in JSON, characters are represented as a single
     // character string
@@ -96,10 +102,10 @@ public final class JsonPrimitive extends JsonElement {
   }
 
   /**
-   * Convenience method to get this element as a boolean value.
-   * If this primitive {@linkplain #isBoolean() is not a boolean}, the string value
-   * is parsed using {@link Boolean#parseBoolean(String)}. This means {@code "true"} (ignoring
-   * case) is considered {@code true} and any other value is considered {@code false}.
+   * Convenience method to get this element as a boolean value. If this primitive {@linkplain
+   * #isBoolean() is not a boolean}, the string value is parsed using {@link
+   * Boolean#parseBoolean(String)}. This means {@code "true"} (ignoring case) is considered {@code
+   * true} and any other value is considered {@code false}.
    */
   @Override
   public boolean getAsBoolean() {
@@ -120,10 +126,9 @@ public final class JsonPrimitive extends JsonElement {
   }
 
   /**
-   * Convenience method to get this element as a {@link Number}.
-   * If this primitive {@linkplain #isString() is a string}, a lazily parsed {@code Number}
-   * is constructed which parses the string when any of its methods are called (which can
-   * lead to a {@link NumberFormatException}).
+   * Convenience method to get this element as a {@link Number}. If this primitive {@linkplain
+   * #isString() is a string}, a lazily parsed {@code Number} is constructed which parses the string
+   * when any of its methods are called (which can lead to a {@link NumberFormatException}).
    *
    * @throws UnsupportedOperationException if this primitive is neither a number nor a string.
    */
@@ -172,7 +177,9 @@ public final class JsonPrimitive extends JsonElement {
    */
   @Override
   public BigDecimal getAsBigDecimal() {
-    return value instanceof BigDecimal ? (BigDecimal) value : new BigDecimal(getAsString());
+    return value instanceof BigDecimal
+        ? (BigDecimal) value
+        : NumberLimits.parseBigDecimal(getAsString());
   }
 
   /**
@@ -184,7 +191,7 @@ public final class JsonPrimitive extends JsonElement {
         ? (BigInteger) value
         : isIntegral(this)
             ? BigInteger.valueOf(this.getAsNumber().longValue())
-            : new BigInteger(this.getAsString());
+            : NumberLimits.parseBigInteger(this.getAsString());
   }
 
   /**
@@ -214,9 +221,9 @@ public final class JsonPrimitive extends JsonElement {
     return isNumber() ? getAsNumber().shortValue() : Short.parseShort(getAsString());
   }
 
- /**
-  * @throws NumberFormatException {@inheritDoc}
-  */
+  /**
+   * @throws NumberFormatException {@inheritDoc}
+   */
   @Override
   public int getAsInt() {
     return isNumber() ? getAsNumber().intValue() : Integer.parseInt(getAsString());
@@ -231,10 +238,9 @@ public final class JsonPrimitive extends JsonElement {
   }
 
   /**
-   * @throws UnsupportedOperationException if the string value of this
-   * primitive is empty.
+   * @throws UnsupportedOperationException if the string value of this primitive is empty.
    * @deprecated This method is misleading, as it does not get this element as a char but rather as
-   * a string's first character.
+   *     a string's first character.
    */
   @Deprecated
   @Override
@@ -247,9 +253,7 @@ public final class JsonPrimitive extends JsonElement {
     }
   }
 
-  /**
-   * Returns the hash code of this object.
-   */
+  /** Returns the hash code of this object. */
   @Override
   public int hashCode() {
     if (value == null) {
@@ -268,9 +272,8 @@ public final class JsonPrimitive extends JsonElement {
   }
 
   /**
-   * Returns whether the other object is equal to this. This method only considers
-   * the other object to be equal if it is an instance of {@code JsonPrimitive} and
-   * has an equal value.
+   * Returns whether the other object is equal to this. This method only considers the other object
+   * to be equal if it is an instance of {@code JsonPrimitive} and has an equal value.
    */
   @Override
   public boolean equals(Object obj) {
@@ -280,34 +283,42 @@ public final class JsonPrimitive extends JsonElement {
     if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
-    JsonPrimitive other = (JsonPrimitive)obj;
+    JsonPrimitive other = (JsonPrimitive) obj;
     if (value == null) {
       return other.value == null;
     }
     if (isIntegral(this) && isIntegral(other)) {
-      return this.value instanceof BigInteger || other.value instanceof BigInteger
+      return (this.value instanceof BigInteger || other.value instanceof BigInteger)
           ? this.getAsBigInteger().equals(other.getAsBigInteger())
           : this.getAsNumber().longValue() == other.getAsNumber().longValue();
     }
     if (value instanceof Number && other.value instanceof Number) {
-      double a = getAsNumber().doubleValue();
-      // Java standard types other than double return true for two NaN. So, need
-      // special handling for double.
-      double b = other.getAsNumber().doubleValue();
-      return a == b || (Double.isNaN(a) && Double.isNaN(b));
+      if (value instanceof BigDecimal && other.value instanceof BigDecimal) {
+        // Uses compareTo to ignore scale of values, e.g. `0` and `0.00` should be considered equal
+        return this.getAsBigDecimal().compareTo(other.getAsBigDecimal()) == 0;
+      }
+
+      double thisAsDouble = this.getAsDouble();
+      double otherAsDouble = other.getAsDouble();
+      // Don't use Double.compare(double, double) because that considers -0.0 and +0.0 not equal
+      return (thisAsDouble == otherAsDouble)
+          || (Double.isNaN(thisAsDouble) && Double.isNaN(otherAsDouble));
     }
     return value.equals(other.value);
   }
 
   /**
-   * Returns true if the specified number is an integral type
-   * (Long, Integer, Short, Byte, BigInteger)
+   * Returns true if the specified number is an integral type (Long, Integer, Short, Byte,
+   * BigInteger)
    */
   private static boolean isIntegral(JsonPrimitive primitive) {
     if (primitive.value instanceof Number) {
       Number number = (Number) primitive.value;
-      return number instanceof BigInteger || number instanceof Long || number instanceof Integer
-          || number instanceof Short || number instanceof Byte;
+      return number instanceof BigInteger
+          || number instanceof Long
+          || number instanceof Integer
+          || number instanceof Short
+          || number instanceof Byte;
     }
     return false;
   }

gson/src/main/java/com/google/gson/JsonSerializationContext.java

@@ -19,8 +19,8 @@ package com.google.gson;
 import java.lang.reflect.Type;
 
 /**
- * Context for serialization that is passed to a custom serializer during invocation of its
- * {@link JsonSerializer#serialize(Object, Type, JsonSerializationContext)} method.
+ * Context for serialization that is passed to a custom serializer during invocation of its {@link
+ * JsonSerializer#serialize(Object, Type, JsonSerializationContext)} method.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -36,10 +36,10 @@ public interface JsonSerializationContext {
   public JsonElement serialize(Object src);
 
   /**
-   * Invokes default serialization on the specified object passing the specific type information.
-   * It should never be invoked on the element received as a parameter of the
-   * {@link JsonSerializer#serialize(Object, Type, JsonSerializationContext)} method. Doing
-   * so will result in an infinite loop since Gson will in-turn call the custom serializer again.
+   * Invokes default serialization on the specified object passing the specific type information. It
+   * should never be invoked on the element received as a parameter of the {@link
+   * JsonSerializer#serialize(Object, Type, JsonSerializationContext)} method. Doing so will result
+   * in an infinite loop since Gson will in-turn call the custom serializer again.
    *
    * @param src the object that needs to be serialized.
    * @param typeOfSrc the actual genericized type of src object.

gson/src/main/java/com/google/gson/JsonSerializer.java

@@ -19,12 +19,12 @@ package com.google.gson;
 import java.lang.reflect.Type;
 
 /**
- * Interface representing a custom serializer for JSON. You should write a custom serializer, if
- * you are not happy with the default serialization done by Gson. You will also need to register
- * this serializer through {@link com.google.gson.GsonBuilder#registerTypeAdapter(Type, Object)}.
+ * Interface representing a custom serializer for JSON. You should write a custom serializer, if you
+ * are not happy with the default serialization done by Gson. You will also need to register this
+ * serializer through {@link com.google.gson.GsonBuilder#registerTypeAdapter(Type, Object)}.
  *
  * <p>Let us look at example where defining a serializer will be useful. The {@code Id} class
- * defined below has two fields: {@code clazz} and {@code value}.</p>
+ * defined below has two fields: {@code clazz} and {@code value}.
  *
  * <pre>
  * public class Id&lt;T&gt; {
@@ -42,10 +42,9 @@ import java.lang.reflect.Type;
  * }
  * </pre>
  *
- * <p>The default serialization of {@code Id(com.foo.MyObject.class, 20L)} will be
- * <code>{"clazz":"com.foo.MyObject","value":20}</code>. Suppose, you just want the output to be
- * the value instead, which is {@code 20} in this case. You can achieve that by writing a custom
- * serializer:</p>
+ * <p>The default serialization of {@code Id(com.foo.MyObject.class, 20L)} will be <code>
+ * {"clazz":"com.foo.MyObject","value":20}</code>. Suppose, you just want the output to be the value
+ * instead, which is {@code 20} in this case. You can achieve that by writing a custom serializer:
  *
  * <pre>
  * class IdSerializer implements JsonSerializer&lt;Id&gt; {
@@ -55,22 +54,22 @@ import java.lang.reflect.Type;
  * }
  * </pre>
  *
- * <p>You will also need to register {@code IdSerializer} with Gson as follows:</p>
+ * <p>You will also need to register {@code IdSerializer} with Gson as follows:
+ *
  * <pre>
  * Gson gson = new GsonBuilder().registerTypeAdapter(Id.class, new IdSerializer()).create();
  * </pre>
  *
- * <p>Serializers should be stateless and thread-safe, otherwise the thread-safety
- * guarantees of {@link Gson} might not apply.
+ * <p>Serializers should be stateless and thread-safe, otherwise the thread-safety guarantees of
+ * {@link Gson} might not apply.
  *
- * <p>New applications should prefer {@link TypeAdapter}, whose streaming API
- * is more efficient than this interface's tree API.
+ * <p>New applications should prefer {@link TypeAdapter}, whose streaming API is more efficient than
+ * this interface's tree API.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
- *
  * @param <T> type for which the serializer is being registered. It is possible that a serializer
- *        may be asked to serialize a specific generic type of the T.
+ *     may be asked to serialize a specific generic type of the T.
  */
 public interface JsonSerializer<T> {
 
@@ -78,11 +77,11 @@ public interface JsonSerializer<T> {
    * Gson invokes this call-back method during serialization when it encounters a field of the
    * specified type.
    *
-   * <p>In the implementation of this call-back method, you should consider invoking
-   * {@link JsonSerializationContext#serialize(Object, Type)} method to create JsonElements for any
-   * non-trivial field of the {@code src} object. However, you should never invoke it on the
-   * {@code src} object itself since that will cause an infinite loop (Gson will call your
-   * call-back method again).</p>
+   * <p>In the implementation of this call-back method, you should consider invoking {@link
+   * JsonSerializationContext#serialize(Object, Type)} method to create JsonElements for any
+   * non-trivial field of the {@code src} object. However, you should never invoke it on the {@code
+   * src} object itself since that will cause an infinite loop (Gson will call your call-back method
+   * again).
    *
    * @param src the object that needs to be converted to Json.
    * @param typeOfSrc the actual type (fully genericized version) of the source object.

gson/src/main/java/com/google/gson/JsonStreamParser.java

@@ -27,8 +27,8 @@ import java.util.NoSuchElementException;
 
 /**
  * A streaming parser that allows reading of multiple {@link JsonElement}s from the specified reader
- * asynchronously. The JSON data is parsed in lenient mode, see also
- * {@link JsonReader#setStrictness(Strictness)}.
+ * asynchronously. The JSON data is parsed in lenient mode, see also {@link
+ * JsonReader#setStrictness(Strictness)}.
  *
  * <p>This class is conditionally thread-safe (see Item 70, Effective Java second edition). To
  * properly use this class across multiple threads, you will need to add some external
@@ -71,8 +71,8 @@ public final class JsonStreamParser implements Iterator<JsonElement> {
   }
 
   /**
-   * Returns the next available {@link JsonElement} on the reader. Throws a
-   * {@link NoSuchElementException} if no element is available.
+   * Returns the next available {@link JsonElement} on the reader. Throws a {@link
+   * NoSuchElementException} if no element is available.
    *
    * @return the next available {@code JsonElement} on the reader.
    * @throws JsonParseException if the incoming stream is malformed JSON.
@@ -96,6 +96,7 @@ public final class JsonStreamParser implements Iterator<JsonElement> {
 
   /**
    * Returns true if a {@link JsonElement} is available on the input for consumption
+   *
    * @return true if a {@link JsonElement} is available on the input, false otherwise
    * @throws JsonParseException if the incoming stream is malformed JSON.
    * @since 1.4
@@ -116,6 +117,7 @@ public final class JsonStreamParser implements Iterator<JsonElement> {
   /**
    * This optional {@link Iterator} method is not relevant for stream parsing and hence is not
    * implemented.
+   *
    * @since 1.4
    */
   @Override

gson/src/main/java/com/google/gson/JsonSyntaxException.java

@@ -16,8 +16,7 @@
 package com.google.gson;
 
 /**
- * This exception is raised when Gson attempts to read (or write) a malformed
- * JSON element.
+ * This exception is raised when Gson attempts to read (or write) a malformed JSON element.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -35,9 +34,8 @@ public final class JsonSyntaxException extends JsonParseException {
   }
 
   /**
-   * Creates exception with the specified cause. Consider using
-   * {@link #JsonSyntaxException(String, Throwable)} instead if you can
-   * describe what actually happened.
+   * Creates exception with the specified cause. Consider using {@link #JsonSyntaxException(String,
+   * Throwable)} instead if you can describe what actually happened.
    *
    * @param cause root exception that caused this exception to be thrown.
    */

gson/src/main/java/com/google/gson/LongSerializationPolicy.java

@@ -20,7 +20,6 @@ package com.google.gson;
  * Defines the expected format for a {@code long} or {@code Long} type when it is serialized.
  *
  * @since 1.3
- *
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
@@ -28,36 +27,36 @@ public enum LongSerializationPolicy {
   /**
    * This is the "default" serialization policy that will output a {@code Long} object as a JSON
    * number. For example, assume an object has a long field named "f" then the serialized output
-   * would be:
-   * {@code {"f":123}}
+   * would be: {@code {"f":123}}
    *
    * <p>A {@code null} value is serialized as {@link JsonNull}.
    */
   DEFAULT() {
-    @Override public JsonElement serialize(Long value) {
+    @Override
+    public JsonElement serialize(Long value) {
       if (value == null) {
         return JsonNull.INSTANCE;
       }
       return new JsonPrimitive(value);
     }
   },
-  
+
   /**
-   * Serializes a long value as a quoted string. For example, assume an object has a long field 
-   * named "f" then the serialized output would be:
-   * {@code {"f":"123"}}
+   * Serializes a long value as a quoted string. For example, assume an object has a long field
+   * named "f" then the serialized output would be: {@code {"f":"123"}}
    *
    * <p>A {@code null} value is serialized as {@link JsonNull}.
    */
   STRING() {
-    @Override public JsonElement serialize(Long value) {
+    @Override
+    public JsonElement serialize(Long value) {
       if (value == null) {
         return JsonNull.INSTANCE;
       }
       return new JsonPrimitive(value.toString());
     }
   };
-  
+
   /**
    * Serialize this {@code value} using this serialization policy.
    *

gson/src/main/java/com/google/gson/ReflectionAccessFilter.java

@@ -20,27 +20,24 @@ import com.google.gson.internal.ReflectionAccessFilterHelper;
 import java.lang.reflect.AccessibleObject;
 
 /**
- * Filter for determining whether reflection based serialization and
- * deserialization is allowed for a class.
+ * Filter for determining whether reflection based serialization and deserialization is allowed for
+ * a class.
  *
- * <p>A filter can be useful in multiple scenarios, for example when
- * upgrading to newer Java versions which use the Java Platform Module
- * System (JPMS). A filter then allows to {@linkplain FilterResult#BLOCK_INACCESSIBLE
- * prevent making inaccessible members accessible}, even if the used
- * Java version might still allow illegal access (but logs a warning),
- * or if {@code java} command line arguments are used to open the inaccessible
- * packages to other parts of the application. This interface defines some
- * convenience filters for this task, such as {@link #BLOCK_INACCESSIBLE_JAVA}.
+ * <p>A filter can be useful in multiple scenarios, for example when upgrading to newer Java
+ * versions which use the Java Platform Module System (JPMS). A filter then allows to {@linkplain
+ * FilterResult#BLOCK_INACCESSIBLE prevent making inaccessible members accessible}, even if the used
+ * Java version might still allow illegal access (but logs a warning), or if {@code java} command
+ * line arguments are used to open the inaccessible packages to other parts of the application. This
+ * interface defines some convenience filters for this task, such as {@link
+ * #BLOCK_INACCESSIBLE_JAVA}.
  *
- * <p>A filter can also be useful to prevent mixing model classes of a
- * project with other non-model classes; the filter could
- * {@linkplain FilterResult#BLOCK_ALL block all reflective access} to
+ * <p>A filter can also be useful to prevent mixing model classes of a project with other non-model
+ * classes; the filter could {@linkplain FilterResult#BLOCK_ALL block all reflective access} to
  * non-model classes.
  *
- * <p>A reflection access filter is similar to an {@link ExclusionStrategy}
- * with the major difference that a filter will cause an exception to be
- * thrown when access is disallowed while an exclusion strategy just skips
- * fields and classes.
+ * <p>A reflection access filter is similar to an {@link ExclusionStrategy} with the major
+ * difference that a filter will cause an exception to be thrown when access is disallowed while an
+ * exclusion strategy just skips fields and classes.
  *
  * @see GsonBuilder#addReflectionAccessFilter(ReflectionAccessFilter)
  * @since 2.9.1
@@ -55,158 +52,177 @@ public interface ReflectionAccessFilter {
     /**
      * Reflection access for the class is allowed.
      *
-     * <p>Note that this does not affect the Java access checks in any way,
-     * it only permits Gson to try using reflection for a class. The Java
-     * runtime might still deny such access.
+     * <p>Note that this does not affect the Java access checks in any way, it only permits Gson to
+     * try using reflection for a class. The Java runtime might still deny such access.
      */
     ALLOW,
     /**
-     * The filter is indecisive whether reflection access should be allowed.
-     * The next registered filter will be consulted to get the result. If
-     * there is no next filter, this result acts like {@link #ALLOW}.
+     * The filter is indecisive whether reflection access should be allowed. The next registered
+     * filter will be consulted to get the result. If there is no next filter, this result acts like
+     * {@link #ALLOW}.
      */
     INDECISIVE,
     /**
-     * Blocks reflection access if a member of the class is not accessible
-     * by default and would have to be made accessible. This is unaffected
-     * by any {@code java} command line arguments being used to make packages
-     * accessible, or by module declaration directives which <i>open</i> the
-     * complete module or certain packages for reflection and will consider
-     * such packages inaccessible.
+     * Blocks reflection access if a member of the class is not accessible by default and would have
+     * to be made accessible. This is unaffected by any {@code java} command line arguments being
+     * used to make packages accessible, or by module declaration directives which <i>open</i> the
+     * complete module or certain packages for reflection and will consider such packages
+     * inaccessible.
      *
-     * <p>Note that this <b>only works for Java 9 and higher</b>, for older
-     * Java versions its functionality will be limited and it might behave like
-     * {@link #ALLOW}. Access checks are only performed as defined by the Java
-     * Language Specification (<a href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-6.html#jls-6.6">JLS 11 &sect;6.6</a>),
-     * restrictions imposed by a {@link SecurityManager} are not considered.
+     * <p>Note that this <b>only works for Java 9 and higher</b>, for older Java versions its
+     * functionality will be limited and it might behave like {@link #ALLOW}. Access checks are only
+     * performed as defined by the Java Language Specification (<a
+     * href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-6.html#jls-6.6">JLS 11
+     * &sect;6.6</a>), restrictions imposed by a {@link SecurityManager} are not considered.
      *
-     * <p>This result type is mainly intended to help enforce the access checks of
-     * the Java Platform Module System. It allows detecting illegal access, even if
-     * the used Java version would only log a warning, or is configured to open
-     * packages for reflection using command line arguments.
+     * <p>This result type is mainly intended to help enforce the access checks of the Java Platform
+     * Module System. It allows detecting illegal access, even if the used Java version would only
+     * log a warning, or is configured to open packages for reflection using command line arguments.
      *
      * @see AccessibleObject#canAccess(Object)
      */
     BLOCK_INACCESSIBLE,
     /**
-     * Blocks all reflection access for the class. Other means for serializing
-     * and deserializing the class, such as a {@link TypeAdapter}, have to
-     * be used.
+     * Blocks all reflection access for the class. Other means for serializing and deserializing the
+     * class, such as a {@link TypeAdapter}, have to be used.
      */
     BLOCK_ALL
   }
 
   /**
-   * Blocks all reflection access to members of standard Java classes which are
-   * not accessible by default. However, reflection access is still allowed for
-   * classes for which all fields are accessible and which have an accessible
-   * no-args constructor (or for which an {@link InstanceCreator} has been registered).
+   * Blocks all reflection access to members of standard Java classes which are not accessible by
+   * default. However, reflection access is still allowed for classes for which all fields are
+   * accessible and which have an accessible no-args constructor (or for which an {@link
+   * InstanceCreator} has been registered).
    *
-   * <p>If this filter encounters a class other than a standard Java class it
-   * returns {@link FilterResult#INDECISIVE}.
+   * <p>If this filter encounters a class other than a standard Java class it returns {@link
+   * FilterResult#INDECISIVE}.
    *
-   * <p>This filter is mainly intended to help enforcing the access checks of
-   * Java Platform Module System. It allows detecting illegal access, even if
-   * the used Java version would only log a warning, or is configured to open
-   * packages for reflection. However, this filter <b>only works for Java 9 and
-   * higher</b>, when using an older Java version its functionality will be
-   * limited.
+   * <p>This filter is mainly intended to help enforcing the access checks of Java Platform Module
+   * System. It allows detecting illegal access, even if the used Java version would only log a
+   * warning, or is configured to open packages for reflection. However, this filter <b>only works
+   * for Java 9 and higher</b>, when using an older Java version its functionality will be limited.
    *
-   * <p>Note that this filter might not cover all standard Java classes. Currently
-   * only classes in a {@code java.*} or {@code javax.*} package are considered. The
-   * set of detected classes might be expanded in the future without prior notice.
+   * <p>Note that this filter might not cover all standard Java classes. Currently only classes in a
+   * {@code java.*} or {@code javax.*} package are considered. The set of detected classes might be
+   * expanded in the future without prior notice.
    *
    * @see FilterResult#BLOCK_INACCESSIBLE
    */
-  ReflectionAccessFilter BLOCK_INACCESSIBLE_JAVA = new ReflectionAccessFilter() {
-    @Override public FilterResult check(Class<?> rawClass) {
-      return ReflectionAccessFilterHelper.isJavaType(rawClass)
-        ? FilterResult.BLOCK_INACCESSIBLE
-        : FilterResult.INDECISIVE;
-    }
-  };
+  ReflectionAccessFilter BLOCK_INACCESSIBLE_JAVA =
+      new ReflectionAccessFilter() {
+        @Override
+        public FilterResult check(Class<?> rawClass) {
+          return ReflectionAccessFilterHelper.isJavaType(rawClass)
+              ? FilterResult.BLOCK_INACCESSIBLE
+              : FilterResult.INDECISIVE;
+        }
+
+        @Override
+        public String toString() {
+          return "ReflectionAccessFilter#BLOCK_INACCESSIBLE_JAVA";
+        }
+      };
 
   /**
    * Blocks all reflection access to members of standard Java classes.
    *
-   * <p>If this filter encounters a class other than a standard Java class it
-   * returns {@link FilterResult#INDECISIVE}.
+   * <p>If this filter encounters a class other than a standard Java class it returns {@link
+   * FilterResult#INDECISIVE}.
    *
-   * <p>This filter is mainly intended to prevent depending on implementation
-   * details of the Java platform and to help applications prepare for upgrading
-   * to the Java Platform Module System.
+   * <p>This filter is mainly intended to prevent depending on implementation details of the Java
+   * platform and to help applications prepare for upgrading to the Java Platform Module System.
    *
-   * <p>Note that this filter might not cover all standard Java classes. Currently
-   * only classes in a {@code java.*} or {@code javax.*} package are considered. The
-   * set of detected classes might be expanded in the future without prior notice.
+   * <p>Note that this filter might not cover all standard Java classes. Currently only classes in a
+   * {@code java.*} or {@code javax.*} package are considered. The set of detected classes might be
+   * expanded in the future without prior notice.
    *
    * @see #BLOCK_INACCESSIBLE_JAVA
    * @see FilterResult#BLOCK_ALL
    */
-  ReflectionAccessFilter BLOCK_ALL_JAVA = new ReflectionAccessFilter() {
-    @Override public FilterResult check(Class<?> rawClass) {
-      return ReflectionAccessFilterHelper.isJavaType(rawClass)
-        ? FilterResult.BLOCK_ALL
-        : FilterResult.INDECISIVE;
-    }
-  };
+  ReflectionAccessFilter BLOCK_ALL_JAVA =
+      new ReflectionAccessFilter() {
+        @Override
+        public FilterResult check(Class<?> rawClass) {
+          return ReflectionAccessFilterHelper.isJavaType(rawClass)
+              ? FilterResult.BLOCK_ALL
+              : FilterResult.INDECISIVE;
+        }
+
+        @Override
+        public String toString() {
+          return "ReflectionAccessFilter#BLOCK_ALL_JAVA";
+        }
+      };
 
   /**
    * Blocks all reflection access to members of standard Android classes.
    *
-   * <p>If this filter encounters a class other than a standard Android class it
-   * returns {@link FilterResult#INDECISIVE}.
+   * <p>If this filter encounters a class other than a standard Android class it returns {@link
+   * FilterResult#INDECISIVE}.
    *
-   * <p>This filter is mainly intended to prevent depending on implementation
-   * details of the Android platform.
+   * <p>This filter is mainly intended to prevent depending on implementation details of the Android
+   * platform.
    *
-   * <p>Note that this filter might not cover all standard Android classes. Currently
-   * only classes in an {@code android.*} or {@code androidx.*} package, and standard
-   * Java classes in a {@code java.*} or {@code javax.*} package are considered. The
-   * set of detected classes might be expanded in the future without prior notice.
+   * <p>Note that this filter might not cover all standard Android classes. Currently only classes
+   * in an {@code android.*} or {@code androidx.*} package, and standard Java classes in a {@code
+   * java.*} or {@code javax.*} package are considered. The set of detected classes might be
+   * expanded in the future without prior notice.
    *
    * @see FilterResult#BLOCK_ALL
    */
-  ReflectionAccessFilter BLOCK_ALL_ANDROID = new ReflectionAccessFilter() {
-    @Override public FilterResult check(Class<?> rawClass) {
-      return ReflectionAccessFilterHelper.isAndroidType(rawClass)
-        ? FilterResult.BLOCK_ALL
-        : FilterResult.INDECISIVE;
-    }
-  };
+  ReflectionAccessFilter BLOCK_ALL_ANDROID =
+      new ReflectionAccessFilter() {
+        @Override
+        public FilterResult check(Class<?> rawClass) {
+          return ReflectionAccessFilterHelper.isAndroidType(rawClass)
+              ? FilterResult.BLOCK_ALL
+              : FilterResult.INDECISIVE;
+        }
+
+        @Override
+        public String toString() {
+          return "ReflectionAccessFilter#BLOCK_ALL_ANDROID";
+        }
+      };
 
   /**
-   * Blocks all reflection access to members of classes belonging to programming
-   * language platforms, such as Java, Android, Kotlin or Scala.
+   * Blocks all reflection access to members of classes belonging to programming language platforms,
+   * such as Java, Android, Kotlin or Scala.
    *
-   * <p>If this filter encounters a class other than a standard platform class it
-   * returns {@link FilterResult#INDECISIVE}.
+   * <p>If this filter encounters a class other than a standard platform class it returns {@link
+   * FilterResult#INDECISIVE}.
    *
-   * <p>This filter is mainly intended to prevent depending on implementation
-   * details of the platform classes.
+   * <p>This filter is mainly intended to prevent depending on implementation details of the
+   * platform classes.
    *
-   * <p>Note that this filter might not cover all platform classes. Currently it
-   * combines the filters {@link #BLOCK_ALL_JAVA} and {@link #BLOCK_ALL_ANDROID},
-   * and checks for other language-specific platform classes like {@code kotlin.*}.
-   * The set of detected classes might be expanded in the future without prior notice.
+   * <p>Note that this filter might not cover all platform classes. Currently it combines the
+   * filters {@link #BLOCK_ALL_JAVA} and {@link #BLOCK_ALL_ANDROID}, and checks for other
+   * language-specific platform classes like {@code kotlin.*}. The set of detected classes might be
+   * expanded in the future without prior notice.
    *
    * @see FilterResult#BLOCK_ALL
    */
-  ReflectionAccessFilter BLOCK_ALL_PLATFORM = new ReflectionAccessFilter() {
-    @Override public FilterResult check(Class<?> rawClass) {
-      return ReflectionAccessFilterHelper.isAnyPlatformType(rawClass)
-        ? FilterResult.BLOCK_ALL
-        : FilterResult.INDECISIVE;
-    }
-  };
+  ReflectionAccessFilter BLOCK_ALL_PLATFORM =
+      new ReflectionAccessFilter() {
+        @Override
+        public FilterResult check(Class<?> rawClass) {
+          return ReflectionAccessFilterHelper.isAnyPlatformType(rawClass)
+              ? FilterResult.BLOCK_ALL
+              : FilterResult.INDECISIVE;
+        }
+
+        @Override
+        public String toString() {
+          return "ReflectionAccessFilter#BLOCK_ALL_PLATFORM";
+        }
+      };
 
   /**
    * Checks if reflection access should be allowed for a class.
    *
-   * @param rawClass
-   *    Class to check
-   * @return
-   *    Result indicating whether reflection access is allowed
+   * @param rawClass Class to check
+   * @return Result indicating whether reflection access is allowed
    */
   FilterResult check(Class<?> rawClass);
 }

gson/src/main/java/com/google/gson/Strictness.java

@@ -4,26 +4,25 @@ import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 
 /**
- * Modes that indicate how strictly a JSON {@linkplain JsonReader reader} or
- * {@linkplain JsonWriter writer} follows the syntax laid out in the
- * <a href="https://www.ietf.org/rfc/rfc8259.txt">RFC 8259 JSON specification</a>.
+ * Modes that indicate how strictly a JSON {@linkplain JsonReader reader} or {@linkplain JsonWriter
+ * writer} follows the syntax laid out in the <a href="https://www.ietf.org/rfc/rfc8259.txt">RFC
+ * 8259 JSON specification</a>.
  *
- * <p>You can look at {@link JsonReader#setStrictness(Strictness)} to see how the strictness
- * affects the {@link JsonReader} and you can look at
- * {@link JsonWriter#setStrictness(Strictness)} to see how the strictness
- * affects the {@link JsonWriter}.</p>
+ * <p>You can look at {@link JsonReader#setStrictness(Strictness)} to see how the strictness affects
+ * the {@link JsonReader} and you can look at {@link JsonWriter#setStrictness(Strictness)} to see
+ * how the strictness affects the {@link JsonWriter}.
  *
  * @see JsonReader#setStrictness(Strictness)
  * @see JsonWriter#setStrictness(Strictness)
  * @since $next-version$
  */
 public enum Strictness {
-    /** Allow large deviations from the JSON specification. */
-    LENIENT,
+  /** Allow large deviations from the JSON specification. */
+  LENIENT,
 
-    /** Allow certain small deviations from the JSON specification for legacy reasons. */
-    LEGACY_STRICT,
+  /** Allow certain small deviations from the JSON specification for legacy reasons. */
+  LEGACY_STRICT,
 
-    /** Strict compliance with the JSON specification. */
-    STRICT
+  /** Strict compliance with the JSON specification. */
+  STRICT
 }

gson/src/main/java/com/google/gson/ToNumberPolicy.java

@@ -17,15 +17,16 @@
 package com.google.gson;
 
 import com.google.gson.internal.LazilyParsedNumber;
+import com.google.gson.internal.NumberLimits;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.MalformedJsonException;
 import java.io.IOException;
 import java.math.BigDecimal;
 
 /**
- * An enumeration that defines two standard number reading strategies and a couple of
- * strategies to overcome some historical Gson limitations while deserializing numbers as
- * {@link Object} and {@link Number}.
+ * An enumeration that defines two standard number reading strategies and a couple of strategies to
+ * overcome some historical Gson limitations while deserializing numbers as {@link Object} and
+ * {@link Number}.
  *
  * @see ToNumberStrategy
  * @since 2.8.9
@@ -33,37 +34,39 @@ import java.math.BigDecimal;
 public enum ToNumberPolicy implements ToNumberStrategy {
 
   /**
-   * Using this policy will ensure that numbers will be read as {@link Double} values.
-   * This is the default strategy used during deserialization of numbers as {@link Object}.
+   * Using this policy will ensure that numbers will be read as {@link Double} values. This is the
+   * default strategy used during deserialization of numbers as {@link Object}.
    */
   DOUBLE {
-    @Override public Double readNumber(JsonReader in) throws IOException {
+    @Override
+    public Double readNumber(JsonReader in) throws IOException {
       return in.nextDouble();
     }
   },
 
   /**
-   * Using this policy will ensure that numbers will be read as a lazily parsed number backed
-   * by a string. This is the default strategy used during deserialization of numbers as
-   * {@link Number}.
+   * Using this policy will ensure that numbers will be read as a lazily parsed number backed by a
+   * string. This is the default strategy used during deserialization of numbers as {@link Number}.
    */
   LAZILY_PARSED_NUMBER {
-    @Override public Number readNumber(JsonReader in) throws IOException {
+    @Override
+    public Number readNumber(JsonReader in) throws IOException {
       return new LazilyParsedNumber(in.nextString());
     }
   },
 
   /**
    * Using this policy will ensure that numbers will be read as {@link Long} or {@link Double}
-   * values depending on how JSON numbers are represented: {@code Long} if the JSON number can
-   * be parsed as a {@code Long} value, or otherwise {@code Double} if it can be parsed as a
-   * {@code Double} value. If the parsed double-precision number results in a positive or negative
-   * infinity ({@link Double#isInfinite()}) or a NaN ({@link Double#isNaN()}) value and the
-   * {@code JsonReader} is not {@link JsonReader#isLenient() lenient}, a {@link MalformedJsonException}
-   * is thrown.
+   * values depending on how JSON numbers are represented: {@code Long} if the JSON number can be
+   * parsed as a {@code Long} value, or otherwise {@code Double} if it can be parsed as a {@code
+   * Double} value. If the parsed double-precision number results in a positive or negative infinity
+   * ({@link Double#isInfinite()}) or a NaN ({@link Double#isNaN()}) value and the {@code
+   * JsonReader} is not {@link JsonReader#isLenient() lenient}, a {@link MalformedJsonException} is
+   * thrown.
    */
   LONG_OR_DOUBLE {
-    @Override public Number readNumber(JsonReader in) throws IOException, JsonParseException {
+    @Override
+    public Number readNumber(JsonReader in) throws IOException, JsonParseException {
       String value = in.nextString();
       try {
         return Long.parseLong(value);
@@ -71,29 +74,32 @@ public enum ToNumberPolicy implements ToNumberStrategy {
         try {
           Double d = Double.valueOf(value);
           if ((d.isInfinite() || d.isNaN()) && !in.isLenient()) {
-            throw new MalformedJsonException("JSON forbids NaN and infinities: " + d + "; at path " + in.getPreviousPath());
+            throw new MalformedJsonException(
+                "JSON forbids NaN and infinities: " + d + "; at path " + in.getPreviousPath());
           }
           return d;
         } catch (NumberFormatException doubleE) {
-          throw new JsonParseException("Cannot parse " + value + "; at path " + in.getPreviousPath(), doubleE);
+          throw new JsonParseException(
+              "Cannot parse " + value + "; at path " + in.getPreviousPath(), doubleE);
         }
       }
     }
   },
 
   /**
-   * Using this policy will ensure that numbers will be read as numbers of arbitrary length
-   * using {@link BigDecimal}.
+   * Using this policy will ensure that numbers will be read as numbers of arbitrary length using
+   * {@link BigDecimal}.
    */
   BIG_DECIMAL {
-    @Override public BigDecimal readNumber(JsonReader in) throws IOException {
+    @Override
+    public BigDecimal readNumber(JsonReader in) throws IOException {
       String value = in.nextString();
       try {
-        return new BigDecimal(value);
+        return NumberLimits.parseBigDecimal(value);
       } catch (NumberFormatException e) {
-        throw new JsonParseException("Cannot parse " + value + "; at path " + in.getPreviousPath(), e);
+        throw new JsonParseException(
+            "Cannot parse " + value + "; at path " + in.getPreviousPath(), e);
       }
     }
   }
-
 }

gson/src/main/java/com/google/gson/ToNumberStrategy.java

@@ -20,20 +20,20 @@ import com.google.gson.stream.JsonReader;
 import java.io.IOException;
 
 /**
- * A strategy that is used to control how numbers should be deserialized for {@link Object} and {@link Number}
- * when a concrete type of the deserialized number is unknown in advance. By default, Gson uses the following
- * deserialization strategies:
+ * A strategy that is used to control how numbers should be deserialized for {@link Object} and
+ * {@link Number} when a concrete type of the deserialized number is unknown in advance. By default,
+ * Gson uses the following deserialization strategies:
  *
  * <ul>
- * <li>{@link Double} values are returned for JSON numbers if the deserialization type is declared as
- * {@code Object}, see {@link ToNumberPolicy#DOUBLE};</li>
- * <li>Lazily parsed number values are returned if the deserialization type is declared as {@code Number},
- * see {@link ToNumberPolicy#LAZILY_PARSED_NUMBER}.</li>
+ *   <li>{@link Double} values are returned for JSON numbers if the deserialization type is declared
+ *       as {@code Object}, see {@link ToNumberPolicy#DOUBLE};
+ *   <li>Lazily parsed number values are returned if the deserialization type is declared as {@code
+ *       Number}, see {@link ToNumberPolicy#LAZILY_PARSED_NUMBER}.
  * </ul>
  *
  * <p>For historical reasons, Gson does not support deserialization of arbitrary-length numbers for
- * {@code Object} and {@code Number} by default, potentially causing precision loss. However,
- * <a href="https://tools.ietf.org/html/rfc8259#section-6">RFC 8259</a> permits this:
+ * {@code Object} and {@code Number} by default, potentially causing precision loss. However, <a
+ * href="https://tools.ietf.org/html/rfc8259#section-6">RFC 8259</a> permits this:
  *
  * <pre>
  *   This specification allows implementations to set limits on the range
@@ -50,7 +50,7 @@ import java.io.IOException;
  * </pre>
  *
  * <p>To overcome the precision loss, use for example {@link ToNumberPolicy#LONG_OR_DOUBLE} or
- * {@link ToNumberPolicy#BIG_DECIMAL}.</p>
+ * {@link ToNumberPolicy#BIG_DECIMAL}.
  *
  * @see ToNumberPolicy
  * @see GsonBuilder#setObjectToNumberStrategy(ToNumberStrategy)
@@ -60,8 +60,8 @@ import java.io.IOException;
 public interface ToNumberStrategy {
 
   /**
-   * Reads a number from the given JSON reader. A strategy is supposed to read a single value from the
-   * reader, and the read value is guaranteed never to be {@code null}.
+   * Reads a number from the given JSON reader. A strategy is supposed to read a single value from
+   * the reader, and the read value is guaranteed never to be {@code null}.
    *
    * @param in JSON reader to read a number from
    * @return number read from the JSON reader.

gson/src/main/java/com/google/gson/TypeAdapter.java

@@ -31,66 +31,69 @@ import java.io.Writer;
  * Converts Java objects to and from JSON.
  *
  * <h2>Defining a type's JSON form</h2>
- * By default Gson converts application classes to JSON using its built-in type
- * adapters. If Gson's default JSON conversion isn't appropriate for a type,
- * extend this class to customize the conversion. Here's an example of a type
- * adapter for an (X,Y) coordinate point: <pre>{@code
- *   public class PointAdapter extends TypeAdapter<Point> {
- *     public Point read(JsonReader reader) throws IOException {
- *       if (reader.peek() == JsonToken.NULL) {
- *         reader.nextNull();
- *         return null;
- *       }
- *       String xy = reader.nextString();
- *       String[] parts = xy.split(",");
- *       int x = Integer.parseInt(parts[0]);
- *       int y = Integer.parseInt(parts[1]);
- *       return new Point(x, y);
+ *
+ * By default Gson converts application classes to JSON using its built-in type adapters. If Gson's
+ * default JSON conversion isn't appropriate for a type, extend this class to customize the
+ * conversion. Here's an example of a type adapter for an (X,Y) coordinate point:
+ *
+ * <pre>{@code
+ * public class PointAdapter extends TypeAdapter<Point> {
+ *   public Point read(JsonReader reader) throws IOException {
+ *     if (reader.peek() == JsonToken.NULL) {
+ *       reader.nextNull();
+ *       return null;
  *     }
- *     public void write(JsonWriter writer, Point value) throws IOException {
- *       if (value == null) {
- *         writer.nullValue();
- *         return;
- *       }
- *       String xy = value.getX() + "," + value.getY();
- *       writer.value(xy);
+ *     String xy = reader.nextString();
+ *     String[] parts = xy.split(",");
+ *     int x = Integer.parseInt(parts[0]);
+ *     int y = Integer.parseInt(parts[1]);
+ *     return new Point(x, y);
+ *   }
+ *   public void write(JsonWriter writer, Point value) throws IOException {
+ *     if (value == null) {
+ *       writer.nullValue();
+ *       return;
  *     }
- *   }}</pre>
- * With this type adapter installed, Gson will convert {@code Points} to JSON as
- * strings like {@code "5,8"} rather than objects like {@code {"x":5,"y":8}}. In
- * this case the type adapter binds a rich Java class to a compact JSON value.
+ *     String xy = value.getX() + "," + value.getY();
+ *     writer.value(xy);
+ *   }
+ * }
+ * }</pre>
  *
- * <p>The {@link #read(JsonReader) read()} method must read exactly one value
- * and {@link #write(JsonWriter,Object) write()} must write exactly one value.
- * For primitive types this is means readers should make exactly one call to
- * {@code nextBoolean()}, {@code nextDouble()}, {@code nextInt()}, {@code
- * nextLong()}, {@code nextString()} or {@code nextNull()}. Writers should make
- * exactly one call to one of <code>value()</code> or <code>nullValue()</code>.
- * For arrays, type adapters should start with a call to {@code beginArray()},
- * convert all elements, and finish with a call to {@code endArray()}. For
- * objects, they should start with {@code beginObject()}, convert the object,
- * and finish with {@code endObject()}. Failing to convert a value or converting
- * too many values may cause the application to crash.
+ * With this type adapter installed, Gson will convert {@code Points} to JSON as strings like {@code
+ * "5,8"} rather than objects like {@code {"x":5,"y":8}}. In this case the type adapter binds a rich
+ * Java class to a compact JSON value.
  *
- * <p>Type adapters should be prepared to read null from the stream and write it
- * to the stream. Alternatively, they should use {@link #nullSafe()} method while
- * registering the type adapter with Gson. If your {@code Gson} instance
- * has been configured to {@link GsonBuilder#serializeNulls()}, these nulls will be
- * written to the final document. Otherwise the value (and the corresponding name
- * when writing to a JSON object) will be omitted automatically. In either case
- * your type adapter must handle null.
+ * <p>The {@link #read(JsonReader) read()} method must read exactly one value and {@link
+ * #write(JsonWriter,Object) write()} must write exactly one value. For primitive types this is
+ * means readers should make exactly one call to {@code nextBoolean()}, {@code nextDouble()}, {@code
+ * nextInt()}, {@code nextLong()}, {@code nextString()} or {@code nextNull()}. Writers should make
+ * exactly one call to one of {@code value()} or {@code nullValue()}. For arrays, type adapters
+ * should start with a call to {@code beginArray()}, convert all elements, and finish with a call to
+ * {@code endArray()}. For objects, they should start with {@code beginObject()}, convert the
+ * object, and finish with {@code endObject()}. Failing to convert a value or converting too many
+ * values may cause the application to crash.
  *
- * <p>Type adapters should be stateless and thread-safe, otherwise the thread-safety
- * guarantees of {@link Gson} might not apply.
+ * <p>Type adapters should be prepared to read null from the stream and write it to the stream.
+ * Alternatively, they should use {@link #nullSafe()} method while registering the type adapter with
+ * Gson. If your {@code Gson} instance has been configured to {@link GsonBuilder#serializeNulls()},
+ * these nulls will be written to the final document. Otherwise the value (and the corresponding
+ * name when writing to a JSON object) will be omitted automatically. In either case your type
+ * adapter must handle null.
  *
- * <p>To use a custom type adapter with Gson, you must <i>register</i> it with a
- * {@link GsonBuilder}: <pre>{@code
- *   GsonBuilder builder = new GsonBuilder();
- *   builder.registerTypeAdapter(Point.class, new PointAdapter());
- *   // if PointAdapter didn't check for nulls in its read/write methods, you should instead use
- *   // builder.registerTypeAdapter(Point.class, new PointAdapter().nullSafe());
- *   ...
- *   Gson gson = builder.create();
+ * <p>Type adapters should be stateless and thread-safe, otherwise the thread-safety guarantees of
+ * {@link Gson} might not apply.
+ *
+ * <p>To use a custom type adapter with Gson, you must <i>register</i> it with a {@link
+ * GsonBuilder}:
+ *
+ * <pre>{@code
+ * GsonBuilder builder = new GsonBuilder();
+ * builder.registerTypeAdapter(Point.class, new PointAdapter());
+ * // if PointAdapter didn't check for nulls in its read/write methods, you should instead use
+ * // builder.registerTypeAdapter(Point.class, new PointAdapter().nullSafe());
+ * ...
+ * Gson gson = builder.create();
  * }</pre>
  *
  * @since 2.1
@@ -117,12 +120,10 @@ import java.io.Writer;
 //
 public abstract class TypeAdapter<T> {
 
-  public TypeAdapter() {
-  }
+  public TypeAdapter() {}
 
   /**
-   * Writes one JSON value (an array, object, string, number, boolean or null)
-   * for {@code value}.
+   * Writes one JSON value (an array, object, string, number, boolean or null) for {@code value}.
    *
    * @param value the Java object to write. May be null.
    */
@@ -131,9 +132,9 @@ public abstract class TypeAdapter<T> {
   /**
    * Converts {@code value} to a JSON document and writes it to {@code out}.
    *
-   * <p>A {@link JsonWriter} with default configuration is used for writing the
-   * JSON data. To customize this behavior, create a {@link JsonWriter}, configure
-   * it and then use {@link #write(JsonWriter, Object)} instead.
+   * <p>A {@link JsonWriter} with default configuration is used for writing the JSON data. To
+   * customize this behavior, create a {@link JsonWriter}, configure it and then use {@link
+   * #write(JsonWriter, Object)} instead.
    *
    * @param value the Java object to convert. May be {@code null}.
    * @since 2.2
@@ -143,71 +144,15 @@ public abstract class TypeAdapter<T> {
     write(writer, value);
   }
 
-  /**
-   * This wrapper method is used to make a type adapter null tolerant. In general, a
-   * type adapter is required to handle nulls in write and read methods. Here is how this
-   * is typically done:<br>
-   * <pre>{@code
-   * Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
-   *   new TypeAdapter<Foo>() {
-   *     public Foo read(JsonReader in) throws IOException {
-   *       if (in.peek() == JsonToken.NULL) {
-   *         in.nextNull();
-   *         return null;
-   *       }
-   *       // read a Foo from in and return it
-   *     }
-   *     public void write(JsonWriter out, Foo src) throws IOException {
-   *       if (src == null) {
-   *         out.nullValue();
-   *         return;
-   *       }
-   *       // write src as JSON to out
-   *     }
-   *   }).create();
-   * }</pre>
-   * You can avoid this boilerplate handling of nulls by wrapping your type adapter with
-   * this method. Here is how we will rewrite the above example:
-   * <pre>{@code
-   * Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
-   *   new TypeAdapter<Foo>() {
-   *     public Foo read(JsonReader in) throws IOException {
-   *       // read a Foo from in and return it
-   *     }
-   *     public void write(JsonWriter out, Foo src) throws IOException {
-   *       // write src as JSON to out
-   *     }
-   *   }.nullSafe()).create();
-   * }</pre>
-   * Note that we didn't need to check for nulls in our type adapter after we used nullSafe.
-   */
-  public final TypeAdapter<T> nullSafe() {
-    return new TypeAdapter<T>() {
-      @Override public void write(JsonWriter out, T value) throws IOException {
-        if (value == null) {
-          out.nullValue();
-        } else {
-          TypeAdapter.this.write(out, value);
-        }
-      }
-      @Override public T read(JsonReader reader) throws IOException {
-        if (reader.peek() == JsonToken.NULL) {
-          reader.nextNull();
-          return null;
-        }
-        return TypeAdapter.this.read(reader);
-      }
-    };
-  }
-
   /**
    * Converts {@code value} to a JSON document.
    *
-   * <p>A {@link JsonWriter} with default configuration is used for writing the
-   * JSON data. To customize this behavior, create a {@link JsonWriter}, configure
-   * it and then use {@link #write(JsonWriter, Object)} instead.
+   * <p>A {@link JsonWriter} with default configuration is used for writing the JSON data. To
+   * customize this behavior, create a {@link JsonWriter}, configure it and then use {@link
+   * #write(JsonWriter, Object)} instead.
    *
-   * @throws JsonIOException wrapping {@code IOException}s thrown by {@link #write(JsonWriter, Object)}
+   * @throws JsonIOException wrapping {@code IOException}s thrown by {@link #write(JsonWriter,
+   *     Object)}
    * @param value the Java object to convert. May be {@code null}.
    * @since 2.2
    */
@@ -226,7 +171,8 @@ public abstract class TypeAdapter<T> {
    *
    * @param value the Java object to convert. May be {@code null}.
    * @return the converted JSON tree. May be {@link JsonNull}.
-   * @throws JsonIOException wrapping {@code IOException}s thrown by {@link #write(JsonWriter, Object)}
+   * @throws JsonIOException wrapping {@code IOException}s thrown by {@link #write(JsonWriter,
+   *     Object)}
    * @since 2.2
    */
   public final JsonElement toJsonTree(T value) {
@@ -240,8 +186,8 @@ public abstract class TypeAdapter<T> {
   }
 
   /**
-   * Reads one JSON value (an array, object, string, number, boolean or null)
-   * and converts it to a Java object. Returns the converted object.
+   * Reads one JSON value (an array, object, string, number, boolean or null) and converts it to a
+   * Java object. Returns the converted object.
    *
    * @return the converted Java object. May be {@code null}.
    */
@@ -250,13 +196,13 @@ public abstract class TypeAdapter<T> {
   /**
    * Converts the JSON document in {@code in} to a Java object.
    *
-   * <p>A {@link JsonReader} with default configuration (that is with
-   * {@link Strictness#LEGACY_STRICT} as strictness) is used for reading the JSON data.
-   * To customize this behavior, create a {@link JsonReader}, configure it and then
-   * use {@link #read(JsonReader)} instead.
+   * <p>A {@link JsonReader} with default configuration (that is with {@link
+   * Strictness#LEGACY_STRICT} as strictness) is used for reading the JSON data. To customize this
+   * behavior, create a {@link JsonReader}, configure it and then use {@link #read(JsonReader)}
+   * instead.
    *
-   * <p>No exception is thrown if the JSON data has multiple top-level JSON elements,
-   * or if there is trailing data.
+   * <p>No exception is thrown if the JSON data has multiple top-level JSON elements, or if there is
+   * trailing data.
    *
    * @return the converted Java object. May be {@code null}.
    * @since 2.2
@@ -269,13 +215,13 @@ public abstract class TypeAdapter<T> {
   /**
    * Converts the JSON document in {@code json} to a Java object.
    *
-   * <p>A {@link JsonReader} with default configuration (that is with
-   * {@link Strictness#LEGACY_STRICT} as strictness) is used for reading the JSON data.
-   * To customize this behavior, create a {@link JsonReader}, configure it and then
-   * use {@link #read(JsonReader)} instead.
+   * <p>A {@link JsonReader} with default configuration (that is with {@link
+   * Strictness#LEGACY_STRICT} as strictness) is used for reading the JSON data. To customize this
+   * behavior, create a {@link JsonReader}, configure it and then use {@link #read(JsonReader)}
+   * instead.
    *
-   * <p>No exception is thrown if the JSON data has multiple top-level JSON elements,
-   * or if there is trailing data.
+   * <p>No exception is thrown if the JSON data has multiple top-level JSON elements, or if there is
+   * trailing data.
    *
    * @return the converted Java object. May be {@code null}.
    * @since 2.2
@@ -300,4 +246,67 @@ public abstract class TypeAdapter<T> {
       throw new JsonIOException(e);
     }
   }
+
+  /**
+   * This wrapper method is used to make a type adapter null tolerant. In general, a type adapter is
+   * required to handle nulls in write and read methods. Here is how this is typically done:<br>
+   *
+   * <pre>{@code
+   * Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
+   *   new TypeAdapter<Foo>() {
+   *     public Foo read(JsonReader in) throws IOException {
+   *       if (in.peek() == JsonToken.NULL) {
+   *         in.nextNull();
+   *         return null;
+   *       }
+   *       // read a Foo from in and return it
+   *     }
+   *     public void write(JsonWriter out, Foo src) throws IOException {
+   *       if (src == null) {
+   *         out.nullValue();
+   *         return;
+   *       }
+   *       // write src as JSON to out
+   *     }
+   *   }).create();
+   * }</pre>
+   *
+   * You can avoid this boilerplate handling of nulls by wrapping your type adapter with this
+   * method. Here is how we will rewrite the above example:
+   *
+   * <pre>{@code
+   * Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
+   *   new TypeAdapter<Foo>() {
+   *     public Foo read(JsonReader in) throws IOException {
+   *       // read a Foo from in and return it
+   *     }
+   *     public void write(JsonWriter out, Foo src) throws IOException {
+   *       // write src as JSON to out
+   *     }
+   *   }.nullSafe()).create();
+   * }</pre>
+   *
+   * Note that we didn't need to check for nulls in our type adapter after we used nullSafe.
+   */
+  public final TypeAdapter<T> nullSafe() {
+    return new TypeAdapter<T>() {
+      @Override
+      public void write(JsonWriter out, T value) throws IOException {
+        if (value == null) {
+          out.nullValue();
+        } else {
+          TypeAdapter.this.write(out, value);
+        }
+      }
+
+      @Override
+      public T read(JsonReader reader) throws IOException {
+        if (reader.peek() == JsonToken.NULL) {
+          reader.nextNull();
+          return null;
+        }
+        return TypeAdapter.this.read(reader);
+      }
+    };
+  }
 }

gson/src/main/java/com/google/gson/TypeAdapterFactory.java

@@ -19,153 +19,152 @@ package com.google.gson;
 import com.google.gson.reflect.TypeToken;
 
 /**
- * Creates type adapters for set of related types. Type adapter factories are
- * most useful when several types share similar structure in their JSON form.
+ * Creates type adapters for set of related types. Type adapter factories are most useful when
+ * several types share similar structure in their JSON form.
  *
  * <h2>Examples</h2>
+ *
  * <h3>Example: Converting enums to lowercase</h3>
- * In this example, we implement a factory that creates type adapters for all
- * enums. The type adapters will write enums in lowercase, despite the fact
- * that they're defined in {@code CONSTANT_CASE} in the corresponding Java
- * model: <pre>   {@code
  *
- *   public class LowercaseEnumTypeAdapterFactory implements TypeAdapterFactory {
- *     public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
- *       Class<T> rawType = (Class<T>) type.getRawType();
- *       if (!rawType.isEnum()) {
- *         return null;
- *       }
+ * In this example, we implement a factory that creates type adapters for all enums. The type
+ * adapters will write enums in lowercase, despite the fact that they're defined in {@code
+ * CONSTANT_CASE} in the corresponding Java model:
  *
- *       final Map<String, T> lowercaseToConstant = new HashMap<>();
- *       for (T constant : rawType.getEnumConstants()) {
- *         lowercaseToConstant.put(toLowercase(constant), constant);
- *       }
- *
- *       return new TypeAdapter<T>() {
- *         public void write(JsonWriter out, T value) throws IOException {
- *           if (value == null) {
- *             out.nullValue();
- *           } else {
- *             out.value(toLowercase(value));
- *           }
- *         }
- *
- *         public T read(JsonReader reader) throws IOException {
- *           if (reader.peek() == JsonToken.NULL) {
- *             reader.nextNull();
- *             return null;
- *           } else {
- *             return lowercaseToConstant.get(reader.nextString());
- *           }
- *         }
- *       };
+ * <pre>{@code
+ * public class LowercaseEnumTypeAdapterFactory implements TypeAdapterFactory {
+ *   public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+ *     Class<T> rawType = (Class<T>) type.getRawType();
+ *     if (!rawType.isEnum()) {
+ *       return null;
  *     }
  *
- *     private String toLowercase(Object o) {
- *       return o.toString().toLowerCase(Locale.US);
+ *     final Map<String, T> lowercaseToConstant = new HashMap<>();
+ *     for (T constant : rawType.getEnumConstants()) {
+ *       lowercaseToConstant.put(toLowercase(constant), constant);
  *     }
+ *
+ *     return new TypeAdapter<T>() {
+ *       public void write(JsonWriter out, T value) throws IOException {
+ *         if (value == null) {
+ *           out.nullValue();
+ *         } else {
+ *           out.value(toLowercase(value));
+ *         }
+ *       }
+ *
+ *       public T read(JsonReader reader) throws IOException {
+ *         if (reader.peek() == JsonToken.NULL) {
+ *           reader.nextNull();
+ *           return null;
+ *         } else {
+ *           return lowercaseToConstant.get(reader.nextString());
+ *         }
+ *       }
+ *     };
  *   }
+ *
+ *   private String toLowercase(Object o) {
+ *     return o.toString().toLowerCase(Locale.US);
+ *   }
+ * }
  * }</pre>
  *
- * <p>Type adapter factories select which types they provide type adapters
- * for. If a factory cannot support a given type, it must return null when
- * that type is passed to {@link #create}. Factories should expect {@code
- * create()} to be called on them for many types and should return null for
- * most of those types. In the above example the factory returns null for
- * calls to {@code create()} where {@code type} is not an enum.
+ * <p>Type adapter factories select which types they provide type adapters for. If a factory cannot
+ * support a given type, it must return null when that type is passed to {@link #create}. Factories
+ * should expect {@code create()} to be called on them for many types and should return null for
+ * most of those types. In the above example the factory returns null for calls to {@code create()}
+ * where {@code type} is not an enum.
  *
- * <p>A factory is typically called once per type, but the returned type
- * adapter may be used many times. It is most efficient to do expensive work
- * like reflection in {@code create()} so that the type adapter's {@code
- * read()} and {@code write()} methods can be very fast. In this example the
+ * <p>A factory is typically called once per type, but the returned type adapter may be used many
+ * times. It is most efficient to do expensive work like reflection in {@code create()} so that the
+ * type adapter's {@code read()} and {@code write()} methods can be very fast. In this example the
  * mapping from lowercase name to enum value is computed eagerly.
  *
  * <p>As with type adapters, factories must be <i>registered</i> with a {@link
- * com.google.gson.GsonBuilder} for them to take effect: <pre>   {@code
+ * com.google.gson.GsonBuilder} for them to take effect:
  *
- *  GsonBuilder builder = new GsonBuilder();
- *  builder.registerTypeAdapterFactory(new LowercaseEnumTypeAdapterFactory());
- *  ...
- *  Gson gson = builder.create();
+ * <pre>{@code
+ * GsonBuilder builder = new GsonBuilder();
+ * builder.registerTypeAdapterFactory(new LowercaseEnumTypeAdapterFactory());
+ * ...
+ * Gson gson = builder.create();
  * }</pre>
- * If multiple factories support the same type, the factory registered earlier
- * takes precedence.
+ *
+ * If multiple factories support the same type, the factory registered earlier takes precedence.
  *
  * <h3>Example: Composing other type adapters</h3>
- * In this example we implement a factory for Guava's {@code Multiset}
- * collection type. The factory can be used to create type adapters for
- * multisets of any element type: the type adapter for {@code
- * Multiset<String>} is different from the type adapter for {@code
- * Multiset<URL>}.
  *
- * <p>The type adapter <i>delegates</i> to another type adapter for the
- * multiset elements. It figures out the element type by reflecting on the
- * multiset's type token. A {@code Gson} is passed in to {@code create} for
- * just this purpose: <pre>   {@code
+ * In this example we implement a factory for Guava's {@code Multiset} collection type. The factory
+ * can be used to create type adapters for multisets of any element type: the type adapter for
+ * {@code Multiset<String>} is different from the type adapter for {@code Multiset<URL>}.
  *
- *   public class MultisetTypeAdapterFactory implements TypeAdapterFactory {
- *     public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
- *       Type type = typeToken.getType();
- *       if (typeToken.getRawType() != Multiset.class
- *           || !(type instanceof ParameterizedType)) {
- *         return null;
+ * <p>The type adapter <i>delegates</i> to another type adapter for the multiset elements. It
+ * figures out the element type by reflecting on the multiset's type token. A {@code Gson} is passed
+ * in to {@code create} for just this purpose:
+ *
+ * <pre>{@code
+ * public class MultisetTypeAdapterFactory implements TypeAdapterFactory {
+ *   public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+ *     Type type = typeToken.getType();
+ *     if (typeToken.getRawType() != Multiset.class
+ *         || !(type instanceof ParameterizedType)) {
+ *       return null;
+ *     }
+ *
+ *     Type elementType = ((ParameterizedType) type).getActualTypeArguments()[0];
+ *     TypeAdapter<?> elementAdapter = gson.getAdapter(TypeToken.get(elementType));
+ *     return (TypeAdapter<T>) newMultisetAdapter(elementAdapter);
+ *   }
+ *
+ *   private <E> TypeAdapter<Multiset<E>> newMultisetAdapter(
+ *       final TypeAdapter<E> elementAdapter) {
+ *     return new TypeAdapter<Multiset<E>>() {
+ *       public void write(JsonWriter out, Multiset<E> value) throws IOException {
+ *         if (value == null) {
+ *           out.nullValue();
+ *           return;
+ *         }
+ *
+ *         out.beginArray();
+ *         for (Multiset.Entry<E> entry : value.entrySet()) {
+ *           out.value(entry.getCount());
+ *           elementAdapter.write(out, entry.getElement());
+ *         }
+ *         out.endArray();
  *       }
  *
- *       Type elementType = ((ParameterizedType) type).getActualTypeArguments()[0];
- *       TypeAdapter<?> elementAdapter = gson.getAdapter(TypeToken.get(elementType));
- *       return (TypeAdapter<T>) newMultisetAdapter(elementAdapter);
- *     }
- *
- *     private <E> TypeAdapter<Multiset<E>> newMultisetAdapter(
- *         final TypeAdapter<E> elementAdapter) {
- *       return new TypeAdapter<Multiset<E>>() {
- *         public void write(JsonWriter out, Multiset<E> value) throws IOException {
- *           if (value == null) {
- *             out.nullValue();
- *             return;
- *           }
- *
- *           out.beginArray();
- *           for (Multiset.Entry<E> entry : value.entrySet()) {
- *             out.value(entry.getCount());
- *             elementAdapter.write(out, entry.getElement());
- *           }
- *           out.endArray();
+ *       public Multiset<E> read(JsonReader in) throws IOException {
+ *         if (in.peek() == JsonToken.NULL) {
+ *           in.nextNull();
+ *           return null;
  *         }
  *
- *         public Multiset<E> read(JsonReader in) throws IOException {
- *           if (in.peek() == JsonToken.NULL) {
- *             in.nextNull();
- *             return null;
- *           }
- *
- *           Multiset<E> result = LinkedHashMultiset.create();
- *           in.beginArray();
- *           while (in.hasNext()) {
- *             int count = in.nextInt();
- *             E element = elementAdapter.read(in);
- *             result.add(element, count);
- *           }
- *           in.endArray();
- *           return result;
+ *         Multiset<E> result = LinkedHashMultiset.create();
+ *         in.beginArray();
+ *         while (in.hasNext()) {
+ *           int count = in.nextInt();
+ *           E element = elementAdapter.read(in);
+ *           result.add(element, count);
  *         }
- *       };
- *     }
+ *         in.endArray();
+ *         return result;
+ *       }
+ *     };
  *   }
+ * }
  * }</pre>
- * Delegating from one type adapter to another is extremely powerful; it's
- * the foundation of how Gson converts Java objects and collections. Whenever
- * possible your factory should retrieve its delegate type adapter in the
- * {@code create()} method; this ensures potentially-expensive type adapter
- * creation happens only once.
+ *
+ * Delegating from one type adapter to another is extremely powerful; it's the foundation of how
+ * Gson converts Java objects and collections. Whenever possible your factory should retrieve its
+ * delegate type adapter in the {@code create()} method; this ensures potentially-expensive type
+ * adapter creation happens only once.
  *
  * @since 2.1
  */
 public interface TypeAdapterFactory {
 
   /**
-   * Returns a type adapter for {@code type}, or null if this factory doesn't
-   * support {@code type}.
+   * Returns a type adapter for {@code type}, or null if this factory doesn't support {@code type}.
    */
   <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type);
 }

gson/src/main/java/com/google/gson/annotations/Expose.java

@@ -23,15 +23,15 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * An annotation that indicates this member should be exposed for JSON
- * serialization or deserialization.
+ * An annotation that indicates this member should be exposed for JSON serialization or
+ * deserialization.
  *
- * <p>This annotation has no effect unless you build {@link com.google.gson.Gson}
- * with a {@link com.google.gson.GsonBuilder} and invoke
- * {@link com.google.gson.GsonBuilder#excludeFieldsWithoutExposeAnnotation()}
- * method.</p>
+ * <p>This annotation has no effect unless you build {@link com.google.gson.Gson} with a {@link
+ * com.google.gson.GsonBuilder} and invoke {@link
+ * com.google.gson.GsonBuilder#excludeFieldsWithoutExposeAnnotation()} method.
  *
  * <p>Here is an example of how this annotation is meant to be used:
+ *
  * <pre>
  * public class User {
  *   &#64;Expose private String firstName;
@@ -40,20 +40,21 @@ import java.lang.annotation.Target;
  *   private String password;
  * }
  * </pre>
- * If you created Gson with {@code new Gson()}, the {@code toJson()} and {@code fromJson()}
- * methods will use the {@code password} field along-with {@code firstName}, {@code lastName},
- * and {@code emailAddress} for serialization and deserialization. However, if you created Gson
- * with {@code Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create()}
- * then the {@code toJson()} and {@code fromJson()} methods of Gson will exclude the
- * {@code password} field. This is because the {@code password} field is not marked with the
- * {@code @Expose} annotation. Gson will also exclude {@code lastName} and {@code emailAddress}
- * from serialization since {@code serialize} is set to {@code false}. Similarly, Gson will
- * exclude {@code emailAddress} from deserialization since {@code deserialize} is set to false.
  *
- * <p>Note that another way to achieve the same effect would have been to just mark the
- * {@code password} field as {@code transient}, and Gson would have excluded it even with default
- * settings. The {@code @Expose} annotation is useful in a style of programming where you want to
- * explicitly specify all fields that should get considered for serialization or deserialization.
+ * If you created Gson with {@code new Gson()}, the {@code toJson()} and {@code fromJson()} methods
+ * will use the {@code password} field along-with {@code firstName}, {@code lastName}, and {@code
+ * emailAddress} for serialization and deserialization. However, if you created Gson with {@code
+ * Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create()} then the {@code
+ * toJson()} and {@code fromJson()} methods of Gson will exclude the {@code password} field. This is
+ * because the {@code password} field is not marked with the {@code @Expose} annotation. Gson will
+ * also exclude {@code lastName} and {@code emailAddress} from serialization since {@code serialize}
+ * is set to {@code false}. Similarly, Gson will exclude {@code emailAddress} from deserialization
+ * since {@code deserialize} is set to false.
+ *
+ * <p>Note that another way to achieve the same effect would have been to just mark the {@code
+ * password} field as {@code transient}, and Gson would have excluded it even with default settings.
+ * The {@code @Expose} annotation is useful in a style of programming where you want to explicitly
+ * specify all fields that should get considered for serialization or deserialization.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -62,19 +63,21 @@ import java.lang.annotation.Target;
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.FIELD)
 public @interface Expose {
-  
+
   /**
    * If {@code true}, the field marked with this annotation is written out in the JSON while
    * serializing. If {@code false}, the field marked with this annotation is skipped from the
    * serialized output. Defaults to {@code true}.
+   *
    * @since 1.4
    */
   public boolean serialize() default true;
 
   /**
-   * If {@code true}, the field marked with this annotation is deserialized from the JSON.
-   * If {@code false}, the field marked with this annotation is skipped during deserialization. 
-   * Defaults to {@code true}.
+   * If {@code true}, the field marked with this annotation is deserialized from the JSON. If {@code
+   * false}, the field marked with this annotation is skipped during deserialization. Defaults to
+   * {@code true}.
+   *
    * @since 1.4
    */
   public boolean deserialize() default true;

gson/src/main/java/com/google/gson/annotations/JsonAdapter.java

@@ -29,10 +29,10 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * An annotation that indicates the Gson {@link TypeAdapter} to use with a class
- * or field.
+ * An annotation that indicates the Gson {@link TypeAdapter} to use with a class or field.
+ *
+ * <p>Here is an example of how this annotation is used:
  *
- * <p>Here is an example of how this annotation is used:</p>
  * <pre>
  * &#64;JsonAdapter(UserJsonAdapter.class)
  * public class User {
@@ -68,6 +68,7 @@ import java.lang.annotation.Target;
  * annotation, it will automatically be invoked to serialize/deserialize {@code User} instances.
  *
  * <p>Here is an example of how to apply this annotation to a field.
+ *
  * <pre>
  * private static final class Gadget {
  *   &#64;JsonAdapter(UserJsonAdapter.class)
@@ -79,39 +80,34 @@ import java.lang.annotation.Target;
  * }
  * </pre>
  *
- * It's possible to specify different type adapters on a field, that
- * field's type, and in the {@link GsonBuilder}. Field annotations
- * take precedence over {@code GsonBuilder}-registered type
+ * It's possible to specify different type adapters on a field, that field's type, and in the {@link
+ * GsonBuilder}. Field annotations take precedence over {@code GsonBuilder}-registered type
  * adapters, which in turn take precedence over annotated types.
  *
- * <p>The class referenced by this annotation must be either a {@link
- * TypeAdapter} or a {@link TypeAdapterFactory}, or must implement one
- * or both of {@link JsonDeserializer} or {@link JsonSerializer}.
- * Using {@link TypeAdapterFactory} makes it possible to delegate
- * to the enclosing {@link Gson} instance. By default the specified
- * adapter will not be called for {@code null} values; set {@link #nullSafe()}
- * to {@code false} to let the adapter handle {@code null} values itself.
+ * <p>The class referenced by this annotation must be either a {@link TypeAdapter} or a {@link
+ * TypeAdapterFactory}, or must implement one or both of {@link JsonDeserializer} or {@link
+ * JsonSerializer}. Using {@link TypeAdapterFactory} makes it possible to delegate to the enclosing
+ * {@link Gson} instance. By default the specified adapter will not be called for {@code null}
+ * values; set {@link #nullSafe()} to {@code false} to let the adapter handle {@code null} values
+ * itself.
+ *
+ * <p>The type adapter is created in the same way Gson creates instances of custom classes during
+ * deserialization, that means:
  *
- * <p>The type adapter is created in the same way Gson creates instances of
- * custom classes during deserialization, that means:
  * <ol>
- *   <li>If a custom {@link InstanceCreator} has been registered for the
- *       adapter class, it will be used to create the instance
- *   <li>Otherwise, if the adapter class has a no-args constructor
- *       (regardless of which visibility), it will be invoked to create
- *       the instance
- *   <li>Otherwise, JDK {@code Unsafe} will be used to create the instance;
- *       see {@link GsonBuilder#disableJdkUnsafe()} for the unexpected
- *       side-effects this might have
+ *   <li>If a custom {@link InstanceCreator} has been registered for the adapter class, it will be
+ *       used to create the instance
+ *   <li>Otherwise, if the adapter class has a no-args constructor (regardless of which visibility),
+ *       it will be invoked to create the instance
+ *   <li>Otherwise, JDK {@code Unsafe} will be used to create the instance; see {@link
+ *       GsonBuilder#disableJdkUnsafe()} for the unexpected side-effects this might have
  * </ol>
  *
- * <p>{@code Gson} instances might cache the adapter they create for
- * a {@code @JsonAdapter} annotation. It is not guaranteed that a new
- * adapter is created every time the annotated class or field is serialized
- * or deserialized.
+ * <p>{@code Gson} instances might cache the adapter they create for a {@code @JsonAdapter}
+ * annotation. It is not guaranteed that a new adapter is created every time the annotated class or
+ * field is serialized or deserialized.
  *
  * @since 2.3
- *
  * @author Inderjeet Singh
  * @author Joel Leitch
  * @author Jesse Wilson
@@ -121,16 +117,19 @@ import java.lang.annotation.Target;
 @Target({ElementType.TYPE, ElementType.FIELD})
 public @interface JsonAdapter {
 
-  /** Either a {@link TypeAdapter} or {@link TypeAdapterFactory}, or one or both of {@link JsonDeserializer} or {@link JsonSerializer}. */
+  /**
+   * Either a {@link TypeAdapter} or {@link TypeAdapterFactory}, or one or both of {@link
+   * JsonDeserializer} or {@link JsonSerializer}.
+   */
   Class<?> value();
 
   /**
-   * Whether the adapter referenced by {@link #value()} should be made {@linkplain TypeAdapter#nullSafe() null-safe}.
+   * Whether the adapter referenced by {@link #value()} should be made {@linkplain
+   * TypeAdapter#nullSafe() null-safe}.
    *
-   * <p>If {@code true} (the default), it will be made null-safe and Gson will handle {@code null} Java objects
-   * on serialization and JSON {@code null} on deserialization without calling the adapter. If {@code false},
-   * the adapter will have to handle the {@code null} values.
+   * <p>If {@code true} (the default), it will be made null-safe and Gson will handle {@code null}
+   * Java objects on serialization and JSON {@code null} on deserialization without calling the
+   * adapter. If {@code false}, the adapter will have to handle the {@code null} values.
    */
   boolean nullSafe() default true;
-
 }

gson/src/main/java/com/google/gson/annotations/SerializedName.java

@@ -23,16 +23,17 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * An annotation that indicates this member should be serialized to JSON with
- * the provided name value as its field name.
+ * An annotation that indicates this member should be serialized to JSON with the provided name
+ * value as its field name.
  *
- * <p>This annotation will override any {@link com.google.gson.FieldNamingPolicy}, including
- * the default field naming policy, that may have been set on the {@link com.google.gson.Gson}
- * instance. A different naming policy can set using the {@code GsonBuilder} class. See
- * {@link com.google.gson.GsonBuilder#setFieldNamingPolicy(com.google.gson.FieldNamingPolicy)}
- * for more information.</p>
+ * <p>This annotation will override any {@link com.google.gson.FieldNamingPolicy}, including the
+ * default field naming policy, that may have been set on the {@link com.google.gson.Gson} instance.
+ * A different naming policy can set using the {@code GsonBuilder} class. See {@link
+ * com.google.gson.GsonBuilder#setFieldNamingPolicy(com.google.gson.FieldNamingPolicy)} for more
+ * information.
+ *
+ * <p>Here is an example of how this annotation is meant to be used:
  *
- * <p>Here is an example of how this annotation is meant to be used:</p>
  * <pre>
  * public class MyClass {
  *   &#64;SerializedName("name") String a;
@@ -47,8 +48,9 @@ import java.lang.annotation.Target;
  * }
  * </pre>
  *
- * <p>The following shows the output that is generated when serializing an instance of the
- * above example class:</p>
+ * <p>The following shows the output that is generated when serializing an instance of the above
+ * example class:
+ *
  * <pre>
  * MyClass target = new MyClass("v1", "v2", "v3");
  * Gson gson = new Gson();
@@ -59,9 +61,10 @@ import java.lang.annotation.Target;
  * {"name":"v1","name1":"v2","c":"v3"}
  * </pre>
  *
- * <p>NOTE: The value you specify in this annotation must be a valid JSON field name.</p>
- * While deserializing, all values specified in the annotation will be deserialized into the field.
- * For example:
+ * <p>NOTE: The value you specify in this annotation must be a valid JSON field name. While
+ * deserializing, all values specified in the annotation will be deserialized into the field. For
+ * example:
+ *
  * <pre>
  *   MyClass target = gson.fromJson("{'name1':'v1'}", MyClass.class);
  *   assertEquals("v1", target.b);
@@ -70,10 +73,10 @@ import java.lang.annotation.Target;
  *   target = gson.fromJson("{'name3':'v3'}", MyClass.class);
  *   assertEquals("v3", target.b);
  * </pre>
+ *
  * Note that MyClass.b is now deserialized from either name1, name2 or name3.
  *
  * @see com.google.gson.FieldNamingPolicy
- *
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
@@ -88,6 +91,7 @@ public @interface SerializedName {
    * @return the desired name of the field when it is serialized or deserialized
    */
   String value();
+
   /**
    * The alternative names of the field when it is deserialized
    *

gson/src/main/java/com/google/gson/annotations/Since.java

@@ -24,14 +24,14 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * An annotation that indicates the version number since a member or a type has been present.
- * This annotation is useful to manage versioning of your JSON classes for a web-service.
+ * An annotation that indicates the version number since a member or a type has been present. This
+ * annotation is useful to manage versioning of your JSON classes for a web-service.
  *
- * <p>
- * This annotation has no effect unless you build {@link com.google.gson.Gson} with a
- * {@code GsonBuilder} and invoke the {@link GsonBuilder#setVersion(double)} method.
+ * <p>This annotation has no effect unless you build {@link com.google.gson.Gson} with a {@code
+ * GsonBuilder} and invoke the {@link GsonBuilder#setVersion(double)} method.
+ *
+ * <p>Here is an example of how this annotation is meant to be used:
  *
- * <p>Here is an example of how this annotation is meant to be used:</p>
  * <pre>
  * public class User {
  *   private String firstName;
@@ -44,9 +44,9 @@ import java.lang.annotation.Target;
  *
  * <p>If you created Gson with {@code new Gson()}, the {@code toJson()} and {@code fromJson()}
  * methods will use all the fields for serialization and deserialization. However, if you created
- * Gson with {@code Gson gson = new GsonBuilder().setVersion(1.0).create()} then the
- * {@code toJson()} and {@code fromJson()} methods of Gson will exclude the {@code address} field
- * since it's version number is set to {@code 1.1}.</p>
+ * Gson with {@code Gson gson = new GsonBuilder().setVersion(1.0).create()} then the {@code
+ * toJson()} and {@code fromJson()} methods of Gson will exclude the {@code address} field since
+ * it's version number is set to {@code 1.1}.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -58,8 +58,8 @@ import java.lang.annotation.Target;
 @Target({ElementType.FIELD, ElementType.TYPE})
 public @interface Since {
   /**
-   * The value indicating a version number since this member or type has been present.
-   * The number is inclusive; annotated elements will be included if {@code gsonVersion >= value}.
+   * The value indicating a version number since this member or type has been present. The number is
+   * inclusive; annotated elements will be included if {@code gsonVersion >= value}.
    */
   double value();
 }

gson/src/main/java/com/google/gson/annotations/Until.java

@@ -25,15 +25,15 @@ import java.lang.annotation.Target;
 
 /**
  * An annotation that indicates the version number until a member or a type should be present.
- * Basically, if Gson is created with a version number that is equal to or exceeds the value
- * stored in the {@code Until} annotation then the field will be ignored from the JSON output.
- * This annotation is useful to manage versioning of your JSON classes for a web-service.
+ * Basically, if Gson is created with a version number that is equal to or exceeds the value stored
+ * in the {@code Until} annotation then the field will be ignored from the JSON output. This
+ * annotation is useful to manage versioning of your JSON classes for a web-service.
  *
- * <p>
- * This annotation has no effect unless you build {@link com.google.gson.Gson} with a
- * {@code GsonBuilder} and invoke the {@link GsonBuilder#setVersion(double)} method.
+ * <p>This annotation has no effect unless you build {@link com.google.gson.Gson} with a {@code
+ * GsonBuilder} and invoke the {@link GsonBuilder#setVersion(double)} method.
+ *
+ * <p>Here is an example of how this annotation is meant to be used:
  *
- * <p>Here is an example of how this annotation is meant to be used:</p>
  * <pre>
  * public class User {
  *   private String firstName;
@@ -45,11 +45,11 @@ import java.lang.annotation.Target;
  *
  * <p>If you created Gson with {@code new Gson()}, the {@code toJson()} and {@code fromJson()}
  * methods will use all the fields for serialization and deserialization. However, if you created
- * Gson with {@code Gson gson = new GsonBuilder().setVersion(1.2).create()} then the
- * {@code toJson()} and {@code fromJson()} methods of Gson will exclude the {@code emailAddress}
- * and {@code password} fields from the example above, because the version number passed to the
- * GsonBuilder, {@code 1.2}, exceeds the version number set on the {@code Until} annotation,
- * {@code 1.1}, for those fields.
+ * Gson with {@code Gson gson = new GsonBuilder().setVersion(1.2).create()} then the {@code
+ * toJson()} and {@code fromJson()} methods of Gson will exclude the {@code emailAddress} and {@code
+ * password} fields from the example above, because the version number passed to the GsonBuilder,
+ * {@code 1.2}, exceeds the version number set on the {@code Until} annotation, {@code 1.1}, for
+ * those fields.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -63,8 +63,8 @@ import java.lang.annotation.Target;
 public @interface Until {
 
   /**
-   * The value indicating a version number until this member or type should be be included.
-   * The number is exclusive; annotated elements will be included if {@code gsonVersion < value}.
+   * The value indicating a version number until this member or type should be included. The number
+   * is exclusive; annotated elements will be included if {@code gsonVersion < value}.
    */
   double value();
 }

gson/src/main/java/com/google/gson/annotations/package-info.java

@@ -16,7 +16,7 @@
 
 /**
  * This package provides annotations that can be used with {@link com.google.gson.Gson}.
- * 
+ *
  * @author Inderjeet Singh, Joel Leitch
  */
 package com.google.gson.annotations;

gson/src/main/java/com/google/gson/internal/$Gson$Preconditions.java

@@ -1,57 +1,57 @@
-/*
- * Copyright (C) 2008 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.google.gson.internal;
-
-import java.util.Objects;
-
-/**
- * A simple utility class used to check method Preconditions.
- *
- * <pre>
- * public long divideBy(long value) {
- *   Preconditions.checkArgument(value != 0);
- *   return this.value / value;
- * }
- * </pre>
- *
- * @author Inderjeet Singh
- * @author Joel Leitch
- */
-public final class $Gson$Preconditions {
-  private $Gson$Preconditions() {
-    throw new UnsupportedOperationException();
-  }
-
-  /**
-   * @deprecated
-   * This is an internal Gson method. Use {@link Objects#requireNonNull(Object)} instead.
-   */
-  // Only deprecated for now because external projects might be using this by accident
-  @Deprecated
-  public static <T> T checkNotNull(T obj) {
-    if (obj == null) {
-      throw new NullPointerException();
-    }
-    return obj;
-  }
-
-  public static void checkArgument(boolean condition) {
-    if (!condition) {
-      throw new IllegalArgumentException();
-    }
-  }
-}
+/*
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.gson.internal;
+
+import java.util.Objects;
+
+/**
+ * A simple utility class used to check method Preconditions.
+ *
+ * <pre>
+ * public long divideBy(long value) {
+ *   Preconditions.checkArgument(value != 0);
+ *   return this.value / value;
+ * }
+ * </pre>
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ */
+public final class $Gson$Preconditions {
+  private $Gson$Preconditions() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * @deprecated This is an internal Gson method. Use {@link Objects#requireNonNull(Object)}
+   *     instead.
+   */
+  // Only deprecated for now because external projects might be using this by accident
+  @Deprecated
+  public static <T> T checkNotNull(T obj) {
+    if (obj == null) {
+      throw new NullPointerException();
+    }
+    return obj;
+  }
+
+  public static void checkArgument(boolean condition) {
+    if (!condition) {
+      throw new IllegalArgumentException();
+    }
+  }
+}

gson/src/main/java/com/google/gson/internal/$Gson$Types.java

@@ -1,4 +1,4 @@
-/**
+/*
  * Copyright (C) 2008 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -50,8 +50,8 @@ public final class $Gson$Types {
   }
 
   /**
-   * Returns a new parameterized type, applying {@code typeArguments} to
-   * {@code rawType} and enclosed by {@code ownerType}.
+   * Returns a new parameterized type, applying {@code typeArguments} to {@code rawType} and
+   * enclosed by {@code ownerType}.
    *
    * @return a {@link java.io.Serializable serializable} parameterized type.
    */
@@ -61,8 +61,7 @@ public final class $Gson$Types {
   }
 
   /**
-   * Returns an array type whose elements are all instances of
-   * {@code componentType}.
+   * Returns an array type whose elements are all instances of {@code componentType}.
    *
    * @return a {@link java.io.Serializable serializable} generic array type.
    */
@@ -71,40 +70,38 @@ public final class $Gson$Types {
   }
 
   /**
-   * Returns a type that represents an unknown type that extends {@code bound}.
-   * For example, if {@code bound} is {@code CharSequence.class}, this returns
-   * {@code ? extends CharSequence}. If {@code bound} is {@code Object.class},
-   * this returns {@code ?}, which is shorthand for {@code ? extends Object}.
+   * Returns a type that represents an unknown type that extends {@code bound}. For example, if
+   * {@code bound} is {@code CharSequence.class}, this returns {@code ? extends CharSequence}. If
+   * {@code bound} is {@code Object.class}, this returns {@code ?}, which is shorthand for {@code ?
+   * extends Object}.
    */
   public static WildcardType subtypeOf(Type bound) {
     Type[] upperBounds;
     if (bound instanceof WildcardType) {
       upperBounds = ((WildcardType) bound).getUpperBounds();
     } else {
-      upperBounds = new Type[] { bound };
+      upperBounds = new Type[] {bound};
     }
     return new WildcardTypeImpl(upperBounds, EMPTY_TYPE_ARRAY);
   }
 
   /**
-   * Returns a type that represents an unknown supertype of {@code bound}. For
-   * example, if {@code bound} is {@code String.class}, this returns {@code ?
-   * super String}.
+   * Returns a type that represents an unknown supertype of {@code bound}. For example, if {@code
+   * bound} is {@code String.class}, this returns {@code ? super String}.
    */
   public static WildcardType supertypeOf(Type bound) {
     Type[] lowerBounds;
     if (bound instanceof WildcardType) {
       lowerBounds = ((WildcardType) bound).getLowerBounds();
     } else {
-      lowerBounds = new Type[] { bound };
+      lowerBounds = new Type[] {bound};
     }
-    return new WildcardTypeImpl(new Type[] { Object.class }, lowerBounds);
+    return new WildcardTypeImpl(new Type[] {Object.class}, lowerBounds);
   }
 
   /**
-   * Returns a type that is functionally equal but not necessarily equal
-   * according to {@link Object#equals(Object) Object.equals()}. The returned
-   * type is {@link java.io.Serializable}.
+   * Returns a type that is functionally equal but not necessarily equal according to {@link
+   * Object#equals(Object) Object.equals()}. The returned type is {@link java.io.Serializable}.
    */
   public static Type canonicalize(Type type) {
     if (type instanceof Class) {
@@ -113,8 +110,8 @@ public final class $Gson$Types {
 
     } else if (type instanceof ParameterizedType) {
       ParameterizedType p = (ParameterizedType) type;
-      return new ParameterizedTypeImpl(p.getOwnerType(),
-          p.getRawType(), p.getActualTypeArguments());
+      return new ParameterizedTypeImpl(
+          p.getOwnerType(), p.getRawType(), p.getActualTypeArguments());
 
     } else if (type instanceof GenericArrayType) {
       GenericArrayType g = (GenericArrayType) type;
@@ -145,7 +142,7 @@ public final class $Gson$Types {
       return (Class<?>) rawType;
 
     } else if (type instanceof GenericArrayType) {
-      Type componentType = ((GenericArrayType)type).getGenericComponentType();
+      Type componentType = ((GenericArrayType) type).getGenericComponentType();
       return Array.newInstance(getRawType(componentType), 0).getClass();
 
     } else if (type instanceof TypeVariable) {
@@ -161,8 +158,11 @@ public final class $Gson$Types {
 
     } else {
       String className = type == null ? "null" : type.getClass().getName();
-      throw new IllegalArgumentException("Expected a Class, ParameterizedType, or "
-          + "GenericArrayType, but <" + type + "> is of type " + className);
+      throw new IllegalArgumentException(
+          "Expected a Class, ParameterizedType, or GenericArrayType, but <"
+              + type
+              + "> is of type "
+              + className);
     }
   }
 
@@ -170,9 +170,7 @@ public final class $Gson$Types {
     return Objects.equals(a, b);
   }
 
-  /**
-   * Returns true if {@code a} and {@code b} are equal.
-   */
+  /** Returns true if {@code a} and {@code b} are equal. */
   public static boolean equals(Type a, Type b) {
     if (a == b) {
       // also handles (a == null && b == null)
@@ -219,7 +217,7 @@ public final class $Gson$Types {
       }
       TypeVariable<?> va = (TypeVariable<?>) a;
       TypeVariable<?> vb = (TypeVariable<?>) b;
-      return va.getGenericDeclaration() == vb.getGenericDeclaration()
+      return Objects.equals(va.getGenericDeclaration(), vb.getGenericDeclaration())
           && va.getName().equals(vb.getName());
 
     } else {
@@ -280,19 +278,23 @@ public final class $Gson$Types {
    */
   private static Type getSupertype(Type context, Class<?> contextRawType, Class<?> supertype) {
     if (context instanceof WildcardType) {
-      // wildcards are useless for resolving supertypes. As the upper bound has the same raw type, use it instead
-      Type[] bounds = ((WildcardType)context).getUpperBounds();
+      // Wildcards are useless for resolving supertypes. As the upper bound has the same raw type,
+      // use it instead
+      Type[] bounds = ((WildcardType) context).getUpperBounds();
       // Currently the JLS only permits one bound for wildcards so using first bound is safe
       assert bounds.length == 1;
       context = bounds[0];
     }
     checkArgument(supertype.isAssignableFrom(contextRawType));
-    return resolve(context, contextRawType,
+    return resolve(
+        context,
+        contextRawType,
         $Gson$Types.getGenericSupertype(context, contextRawType, supertype));
   }
 
   /**
    * Returns the component type of this array type.
+   *
    * @throws ClassCastException if this type is not an array.
    */
   public static Type getArrayComponentType(Type array) {
@@ -303,6 +305,7 @@ public final class $Gson$Types {
 
   /**
    * Returns the element type of this collection type.
+   *
    * @throws IllegalArgumentException if this type is not a collection.
    */
   public static Type getCollectionElementType(Type context, Class<?> contextRawType) {
@@ -315,8 +318,8 @@ public final class $Gson$Types {
   }
 
   /**
-   * Returns a two element array containing this map's key and value types in
-   * positions 0 and 1 respectively.
+   * Returns a two element array containing this map's key and value types in positions 0 and 1
+   * respectively.
    */
   public static Type[] getMapKeyAndValueTypes(Type context, Class<?> contextRawType) {
     /*
@@ -325,7 +328,7 @@ public final class $Gson$Types {
      * extend Hashtable<Object, Object>.
      */
     if (context == Properties.class) {
-      return new Type[] { String.class, String.class }; // TODO: test subclasses of Properties!
+      return new Type[] {String.class, String.class}; // TODO: test subclasses of Properties!
     }
 
     Type mapType = getSupertype(context, contextRawType, Map.class);
@@ -334,7 +337,7 @@ public final class $Gson$Types {
       ParameterizedType mapParameterizedType = (ParameterizedType) mapType;
       return mapParameterizedType.getActualTypeArguments();
     }
-    return new Type[] { Object.class, Object.class };
+    return new Type[] {Object.class, Object.class};
   }
 
   public static Type resolve(Type context, Class<?> contextRawType, Type toResolve) {
@@ -342,8 +345,11 @@ public final class $Gson$Types {
     return resolve(context, contextRawType, toResolve, new HashMap<TypeVariable<?>, Type>());
   }
 
-  private static Type resolve(Type context, Class<?> contextRawType, Type toResolve,
-                              Map<TypeVariable<?>, Type> visitedTypeVariables) {
+  private static Type resolve(
+      Type context,
+      Class<?> contextRawType,
+      Type toResolve,
+      Map<TypeVariable<?>, Type> visitedTypeVariables) {
     // this implementation is made a little more complicated in an attempt to avoid object-creation
     TypeVariable<?> resolving = null;
     while (true) {
@@ -369,19 +375,17 @@ public final class $Gson$Types {
       } else if (toResolve instanceof Class && ((Class<?>) toResolve).isArray()) {
         Class<?> original = (Class<?>) toResolve;
         Type componentType = original.getComponentType();
-        Type newComponentType = resolve(context, contextRawType, componentType, visitedTypeVariables);
-        toResolve = equal(componentType, newComponentType)
-            ? original
-            : arrayOf(newComponentType);
+        Type newComponentType =
+            resolve(context, contextRawType, componentType, visitedTypeVariables);
+        toResolve = equal(componentType, newComponentType) ? original : arrayOf(newComponentType);
         break;
 
       } else if (toResolve instanceof GenericArrayType) {
         GenericArrayType original = (GenericArrayType) toResolve;
         Type componentType = original.getGenericComponentType();
-        Type newComponentType = resolve(context, contextRawType, componentType, visitedTypeVariables);
-        toResolve = equal(componentType, newComponentType)
-            ? original
-            : arrayOf(newComponentType);
+        Type newComponentType =
+            resolve(context, contextRawType, componentType, visitedTypeVariables);
+        toResolve = equal(componentType, newComponentType) ? original : arrayOf(newComponentType);
         break;
 
       } else if (toResolve instanceof ParameterizedType) {
@@ -392,7 +396,8 @@ public final class $Gson$Types {
 
         Type[] args = original.getActualTypeArguments();
         for (int t = 0, length = args.length; t < length; t++) {
-          Type resolvedTypeArgument = resolve(context, contextRawType, args[t], visitedTypeVariables);
+          Type resolvedTypeArgument =
+              resolve(context, contextRawType, args[t], visitedTypeVariables);
           if (!equal(resolvedTypeArgument, args[t])) {
             if (!changed) {
               args = args.clone();
@@ -402,9 +407,10 @@ public final class $Gson$Types {
           }
         }
 
-        toResolve = changed
-            ? newParameterizedTypeWithOwner(newOwnerType, original.getRawType(), args)
-            : original;
+        toResolve =
+            changed
+                ? newParameterizedTypeWithOwner(newOwnerType, original.getRawType(), args)
+                : original;
         break;
 
       } else if (toResolve instanceof WildcardType) {
@@ -413,13 +419,15 @@ public final class $Gson$Types {
         Type[] originalUpperBound = original.getUpperBounds();
 
         if (originalLowerBound.length == 1) {
-          Type lowerBound = resolve(context, contextRawType, originalLowerBound[0], visitedTypeVariables);
+          Type lowerBound =
+              resolve(context, contextRawType, originalLowerBound[0], visitedTypeVariables);
           if (lowerBound != originalLowerBound[0]) {
             toResolve = supertypeOf(lowerBound);
             break;
           }
         } else if (originalUpperBound.length == 1) {
-          Type upperBound = resolve(context, contextRawType, originalUpperBound[0], visitedTypeVariables);
+          Type upperBound =
+              resolve(context, contextRawType, originalUpperBound[0], visitedTypeVariables);
           if (upperBound != originalUpperBound[0]) {
             toResolve = subtypeOf(upperBound);
             break;
@@ -439,7 +447,8 @@ public final class $Gson$Types {
     return toResolve;
   }
 
-  private static Type resolveTypeVariable(Type context, Class<?> contextRawType, TypeVariable<?> unknown) {
+  private static Type resolveTypeVariable(
+      Type context, Class<?> contextRawType, TypeVariable<?> unknown) {
     Class<?> declaredByRaw = declaringClassOf(unknown);
 
     // we can't reduce this further
@@ -471,9 +480,7 @@ public final class $Gson$Types {
    */
   private static Class<?> declaringClassOf(TypeVariable<?> typeVariable) {
     GenericDeclaration genericDeclaration = typeVariable.getGenericDeclaration();
-    return genericDeclaration instanceof Class
-        ? (Class<?>) genericDeclaration
-        : null;
+    return genericDeclaration instanceof Class ? (Class<?>) genericDeclaration : null;
   }
 
   static void checkNotPrimitive(Type type) {
@@ -496,9 +503,18 @@ public final class $Gson$Types {
     return false;
   }
 
+  // Here and below we put @SuppressWarnings("serial") on fields of type `Type`. Recent Java
+  // compilers complain that the declared type is not Serializable. But in this context we go out of
+  // our way to ensure that the Type in question is either Class (which is serializable) or one of
+  // the nested Type implementations here (which are also serializable).
   private static final class ParameterizedTypeImpl implements ParameterizedType, Serializable {
+    @SuppressWarnings("serial")
     private final Type ownerType;
+
+    @SuppressWarnings("serial")
     private final Type rawType;
+
+    @SuppressWarnings("serial")
     private final Type[] typeArguments;
 
     public ParameterizedTypeImpl(Type ownerType, Type rawType, Type... typeArguments) {
@@ -519,19 +535,23 @@ public final class $Gson$Types {
       }
     }
 
-    @Override public Type[] getActualTypeArguments() {
+    @Override
+    public Type[] getActualTypeArguments() {
       return typeArguments.clone();
     }
 
-    @Override public Type getRawType() {
+    @Override
+    public Type getRawType() {
       return rawType;
     }
 
-    @Override public Type getOwnerType() {
+    @Override
+    public Type getOwnerType() {
       return ownerType;
     }
 
-    @Override public boolean equals(Object other) {
+    @Override
+    public boolean equals(Object other) {
       return other instanceof ParameterizedType
           && $Gson$Types.equals(this, (ParameterizedType) other);
     }
@@ -540,20 +560,23 @@ public final class $Gson$Types {
       return o != null ? o.hashCode() : 0;
     }
 
-    @Override public int hashCode() {
-      return Arrays.hashCode(typeArguments)
-          ^ rawType.hashCode()
-          ^ hashCodeOrZero(ownerType);
+    @Override
+    public int hashCode() {
+      return Arrays.hashCode(typeArguments) ^ rawType.hashCode() ^ hashCodeOrZero(ownerType);
     }
 
-    @Override public String toString() {
+    @Override
+    public String toString() {
       int length = typeArguments.length;
       if (length == 0) {
         return typeToString(rawType);
       }
 
       StringBuilder stringBuilder = new StringBuilder(30 * (length + 1));
-      stringBuilder.append(typeToString(rawType)).append("<").append(typeToString(typeArguments[0]));
+      stringBuilder
+          .append(typeToString(rawType))
+          .append("<")
+          .append(typeToString(typeArguments[0]));
       for (int i = 1; i < length; i++) {
         stringBuilder.append(", ").append(typeToString(typeArguments[i]));
       }
@@ -564,6 +587,7 @@ public final class $Gson$Types {
   }
 
   private static final class GenericArrayTypeImpl implements GenericArrayType, Serializable {
+    @SuppressWarnings("serial")
     private final Type componentType;
 
     public GenericArrayTypeImpl(Type componentType) {
@@ -571,20 +595,23 @@ public final class $Gson$Types {
       this.componentType = canonicalize(componentType);
     }
 
-    @Override public Type getGenericComponentType() {
+    @Override
+    public Type getGenericComponentType() {
       return componentType;
     }
 
-    @Override public boolean equals(Object o) {
-      return o instanceof GenericArrayType
-          && $Gson$Types.equals(this, (GenericArrayType) o);
+    @Override
+    public boolean equals(Object o) {
+      return o instanceof GenericArrayType && $Gson$Types.equals(this, (GenericArrayType) o);
     }
 
-    @Override public int hashCode() {
+    @Override
+    public int hashCode() {
       return componentType.hashCode();
     }
 
-    @Override public String toString() {
+    @Override
+    public String toString() {
       return typeToString(componentType) + "[]";
     }
 
@@ -592,13 +619,16 @@ public final class $Gson$Types {
   }
 
   /**
-   * The WildcardType interface supports multiple upper bounds and multiple
-   * lower bounds. We only support what the target Java version supports - at most one
-   * bound, see also https://bugs.openjdk.java.net/browse/JDK-8250660. If a lower bound
-   * is set, the upper bound must be Object.class.
+   * The WildcardType interface supports multiple upper bounds and multiple lower bounds. We only
+   * support what the target Java version supports - at most one bound, see also
+   * https://bugs.openjdk.java.net/browse/JDK-8250660. If a lower bound is set, the upper bound must
+   * be Object.class.
    */
   private static final class WildcardTypeImpl implements WildcardType, Serializable {
+    @SuppressWarnings("serial")
     private final Type upperBound;
+
+    @SuppressWarnings("serial")
     private final Type lowerBound;
 
     public WildcardTypeImpl(Type[] upperBounds, Type[] lowerBounds) {
@@ -620,26 +650,29 @@ public final class $Gson$Types {
       }
     }
 
-    @Override public Type[] getUpperBounds() {
-      return new Type[] { upperBound };
+    @Override
+    public Type[] getUpperBounds() {
+      return new Type[] {upperBound};
     }
 
-    @Override public Type[] getLowerBounds() {
-      return lowerBound != null ? new Type[] { lowerBound } : EMPTY_TYPE_ARRAY;
+    @Override
+    public Type[] getLowerBounds() {
+      return lowerBound != null ? new Type[] {lowerBound} : EMPTY_TYPE_ARRAY;
     }
 
-    @Override public boolean equals(Object other) {
-      return other instanceof WildcardType
-          && $Gson$Types.equals(this, (WildcardType) other);
+    @Override
+    public boolean equals(Object other) {
+      return other instanceof WildcardType && $Gson$Types.equals(this, (WildcardType) other);
     }
 
-    @Override public int hashCode() {
+    @Override
+    public int hashCode() {
       // this equals Arrays.hashCode(getLowerBounds()) ^ Arrays.hashCode(getUpperBounds());
-      return (lowerBound != null ? 31 + lowerBound.hashCode() : 1)
-          ^ (31 + upperBound.hashCode());
+      return (lowerBound != null ? 31 + lowerBound.hashCode() : 1) ^ (31 + upperBound.hashCode());
     }
 
-    @Override public String toString() {
+    @Override
+    public String toString() {
       if (lowerBound != null) {
         return "? super " + typeToString(lowerBound);
       } else if (upperBound == Object.class) {

gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java

@@ -47,23 +47,25 @@ import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ConcurrentNavigableMap;
 import java.util.concurrent.ConcurrentSkipListMap;
 
-/**
- * Returns a function that can construct an instance of a requested type.
- */
+/** Returns a function that can construct an instance of a requested type. */
 public final class ConstructorConstructor {
   private final Map<Type, InstanceCreator<?>> instanceCreators;
   private final boolean useJdkUnsafe;
   private final List<ReflectionAccessFilter> reflectionFilters;
 
-  public ConstructorConstructor(Map<Type, InstanceCreator<?>> instanceCreators, boolean useJdkUnsafe, List<ReflectionAccessFilter> reflectionFilters) {
+  public ConstructorConstructor(
+      Map<Type, InstanceCreator<?>> instanceCreators,
+      boolean useJdkUnsafe,
+      List<ReflectionAccessFilter> reflectionFilters) {
     this.instanceCreators = instanceCreators;
     this.useJdkUnsafe = useJdkUnsafe;
     this.reflectionFilters = reflectionFilters;
   }
 
   /**
-   * Check if the class can be instantiated by Unsafe allocator. If the instance has interface or abstract modifiers
-   * return an exception message.
+   * Check if the class can be instantiated by Unsafe allocator. If the instance has interface or
+   * abstract modifiers return an exception message.
+   *
    * @param c instance of the class to be checked
    * @return if instantiable {@code null}, else a non-{@code null} exception message
    */
@@ -71,7 +73,8 @@ public final class ConstructorConstructor {
     int modifiers = c.getModifiers();
     if (Modifier.isInterface(modifiers)) {
       return "Interfaces can't be instantiated! Register an InstanceCreator"
-          + " or a TypeAdapter for this type. Interface name: " + c.getName();
+          + " or a TypeAdapter for this type. Interface name: "
+          + c.getName();
     }
     if (Modifier.isAbstract(modifiers)) {
       // R8 performs aggressive optimizations where it removes the default constructor of a class
@@ -83,8 +86,10 @@ public final class ConstructorConstructor {
        * still making the class abstract
        */
       return "Abstract classes can't be instantiated! Adjust the R8 configuration or register"
-          + " an InstanceCreator or a TypeAdapter for this type. Class name: " + c.getName()
-          + "\nSee " + TroubleshootingGuide.createUrl("r8-abstract-class");
+          + " an InstanceCreator or a TypeAdapter for this type. Class name: "
+          + c.getName()
+          + "\nSee "
+          + TroubleshootingGuide.createUrl("r8-abstract-class");
     }
     return null;
   }
@@ -99,7 +104,8 @@ public final class ConstructorConstructor {
     final InstanceCreator<T> typeCreator = (InstanceCreator<T>) instanceCreators.get(type);
     if (typeCreator != null) {
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           return typeCreator.createInstance(type);
         }
       };
@@ -107,11 +113,11 @@ public final class ConstructorConstructor {
 
     // Next try raw type match for instance creators
     @SuppressWarnings("unchecked") // types must agree
-    final InstanceCreator<T> rawTypeCreator =
-        (InstanceCreator<T>) instanceCreators.get(rawType);
+    final InstanceCreator<T> rawTypeCreator = (InstanceCreator<T>) instanceCreators.get(rawType);
     if (rawTypeCreator != null) {
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           return rawTypeCreator.createInstance(type);
         }
       };
@@ -125,7 +131,8 @@ public final class ConstructorConstructor {
       return specialConstructor;
     }
 
-    FilterResult filterResult = ReflectionAccessFilterHelper.getFilterResult(reflectionFilters, rawType);
+    FilterResult filterResult =
+        ReflectionAccessFilterHelper.getFilterResult(reflectionFilters, rawType);
     ObjectConstructor<T> defaultConstructor = newDefaultConstructor(rawType, filterResult);
     if (defaultConstructor != null) {
       return defaultConstructor;
@@ -141,7 +148,8 @@ public final class ConstructorConstructor {
     final String exceptionMessage = checkInstantiable(rawType);
     if (exceptionMessage != null) {
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           throw new JsonIOException(exceptionMessage);
         }
       };
@@ -153,11 +161,15 @@ public final class ConstructorConstructor {
       // finally try unsafe
       return newUnsafeAllocator(rawType);
     } else {
-      final String message = "Unable to create instance of " + rawType + "; ReflectionAccessFilter"
-          + " does not permit using reflection or Unsafe. Register an InstanceCreator or a TypeAdapter"
-          + " for this type or adjust the access filter to allow using reflection.";
+      final String message =
+          "Unable to create instance of "
+              + rawType
+              + "; ReflectionAccessFilter does not permit using reflection or Unsafe. Register an"
+              + " InstanceCreator or a TypeAdapter for this type or adjust the access filter to"
+              + " allow using reflection.";
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           throw new JsonIOException(message);
         }
       };
@@ -165,17 +177,20 @@ public final class ConstructorConstructor {
   }
 
   /**
-   * Creates constructors for special JDK collection types which do not have a public no-args constructor.
+   * Creates constructors for special JDK collection types which do not have a public no-args
+   * constructor.
    */
-  private static <T> ObjectConstructor<T> newSpecialCollectionConstructor(final Type type, Class<? super T> rawType) {
+  private static <T> ObjectConstructor<T> newSpecialCollectionConstructor(
+      final Type type, Class<? super T> rawType) {
     if (EnumSet.class.isAssignableFrom(rawType)) {
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           if (type instanceof ParameterizedType) {
             Type elementType = ((ParameterizedType) type).getActualTypeArguments()[0];
             if (elementType instanceof Class) {
               @SuppressWarnings({"unchecked", "rawtypes"})
-              T set = (T) EnumSet.noneOf((Class)elementType);
+              T set = (T) EnumSet.noneOf((Class) elementType);
               return set;
             } else {
               throw new JsonIOException("Invalid EnumSet type: " + type.toString());
@@ -190,7 +205,8 @@ public final class ConstructorConstructor {
     // and constructor parameter might have completely different meaning
     else if (rawType == EnumMap.class) {
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           if (type instanceof ParameterizedType) {
             Type elementType = ((ParameterizedType) type).getActualTypeArguments()[0];
             if (elementType instanceof Class) {
@@ -210,7 +226,8 @@ public final class ConstructorConstructor {
     return null;
   }
 
-  private static <T> ObjectConstructor<T> newDefaultConstructor(Class<? super T> rawType, FilterResult filterResult) {
+  private static <T> ObjectConstructor<T> newDefaultConstructor(
+      Class<? super T> rawType, FilterResult filterResult) {
     // Cannot invoke constructor of abstract class
     if (Modifier.isAbstract(rawType.getModifiers())) {
       return null;
@@ -223,17 +240,25 @@ public final class ConstructorConstructor {
       return null;
     }
 
-    boolean canAccess = filterResult == FilterResult.ALLOW || (ReflectionAccessFilterHelper.canAccess(constructor, null)
-        // Be a bit more lenient here for BLOCK_ALL; if constructor is accessible and public then allow calling it
-        && (filterResult != FilterResult.BLOCK_ALL || Modifier.isPublic(constructor.getModifiers())));
+    boolean canAccess =
+        filterResult == FilterResult.ALLOW
+            || (ReflectionAccessFilterHelper.canAccess(constructor, null)
+                // Be a bit more lenient here for BLOCK_ALL; if constructor is accessible and public
+                // then allow calling it
+                && (filterResult != FilterResult.BLOCK_ALL
+                    || Modifier.isPublic(constructor.getModifiers())));
 
     if (!canAccess) {
-      final String message = "Unable to invoke no-args constructor of " + rawType + ";"
-          + " constructor is not accessible and ReflectionAccessFilter does not permit making"
-          + " it accessible. Register an InstanceCreator or a TypeAdapter for this type, change"
-          + " the visibility of the constructor or adjust the access filter.";
+      final String message =
+          "Unable to invoke no-args constructor of "
+              + rawType
+              + ";"
+              + " constructor is not accessible and ReflectionAccessFilter does not permit making"
+              + " it accessible. Register an InstanceCreator or a TypeAdapter for this type, change"
+              + " the visibility of the constructor or adjust the access filter.";
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           throw new JsonIOException(message);
         }
       };
@@ -265,22 +290,29 @@ public final class ConstructorConstructor {
     }
 
     return new ObjectConstructor<T>() {
-      @Override public T construct() {
+      @Override
+      public T construct() {
         try {
           @SuppressWarnings("unchecked") // T is the same raw type as is requested
           T newInstance = (T) constructor.newInstance();
           return newInstance;
         }
-        // Note: InstantiationException should be impossible because check at start of method made sure
-        //   that class is not abstract
+        // Note: InstantiationException should be impossible because check at start of method made
+        // sure that class is not abstract
         catch (InstantiationException e) {
-          throw new RuntimeException("Failed to invoke constructor '" + ReflectionHelper.constructorToString(constructor) + "'"
-              + " with no args", e);
+          throw new RuntimeException(
+              "Failed to invoke constructor '"
+                  + ReflectionHelper.constructorToString(constructor)
+                  + "' with no args",
+              e);
         } catch (InvocationTargetException e) {
           // TODO: don't wrap if cause is unchecked?
           // TODO: JsonParseException ?
-          throw new RuntimeException("Failed to invoke constructor '" + ReflectionHelper.constructorToString(constructor) + "'"
-              + " with no args", e.getCause());
+          throw new RuntimeException(
+              "Failed to invoke constructor '"
+                  + ReflectionHelper.constructorToString(constructor)
+                  + "' with no args",
+              e.getCause());
         } catch (IllegalAccessException e) {
           throw ReflectionHelper.createExceptionForUnexpectedIllegalAccess(e);
         }
@@ -288,10 +320,7 @@ public final class ConstructorConstructor {
     };
   }
 
-  /**
-   * Constructors for common interface types like Map and List and their
-   * subtypes.
-   */
+  /** Constructors for common interface types like Map and List and their subtypes. */
   @SuppressWarnings("unchecked") // use runtime checks to guarantee that 'T' is what it is
   private static <T> ObjectConstructor<T> newDefaultImplementationConstructor(
       final Type type, Class<? super T> rawType) {
@@ -307,25 +336,29 @@ public final class ConstructorConstructor {
     if (Collection.class.isAssignableFrom(rawType)) {
       if (SortedSet.class.isAssignableFrom(rawType)) {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new TreeSet<>();
           }
         };
       } else if (Set.class.isAssignableFrom(rawType)) {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new LinkedHashSet<>();
           }
         };
       } else if (Queue.class.isAssignableFrom(rawType)) {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new ArrayDeque<>();
           }
         };
       } else {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new ArrayList<>();
           }
         };
@@ -335,32 +368,38 @@ public final class ConstructorConstructor {
     if (Map.class.isAssignableFrom(rawType)) {
       if (ConcurrentNavigableMap.class.isAssignableFrom(rawType)) {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new ConcurrentSkipListMap<>();
           }
         };
       } else if (ConcurrentMap.class.isAssignableFrom(rawType)) {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new ConcurrentHashMap<>();
           }
         };
       } else if (SortedMap.class.isAssignableFrom(rawType)) {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new TreeMap<>();
           }
         };
-      } else if (type instanceof ParameterizedType && !String.class.isAssignableFrom(
-          TypeToken.get(((ParameterizedType) type).getActualTypeArguments()[0]).getRawType())) {
+      } else if (type instanceof ParameterizedType
+          && !String.class.isAssignableFrom(
+              TypeToken.get(((ParameterizedType) type).getActualTypeArguments()[0]).getRawType())) {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new LinkedHashMap<>();
           }
         };
       } else {
         return new ObjectConstructor<T>() {
-          @Override public T construct() {
+          @Override
+          public T construct() {
             return (T) new LinkedTreeMap<>();
           }
         };
@@ -373,41 +412,52 @@ public final class ConstructorConstructor {
   private <T> ObjectConstructor<T> newUnsafeAllocator(final Class<? super T> rawType) {
     if (useJdkUnsafe) {
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           try {
             @SuppressWarnings("unchecked")
             T newInstance = (T) UnsafeAllocator.INSTANCE.newInstance(rawType);
             return newInstance;
           } catch (Exception e) {
-            throw new RuntimeException(("Unable to create instance of " + rawType + "."
-                + " Registering an InstanceCreator or a TypeAdapter for this type, or adding a no-args"
-                + " constructor may fix this problem."), e);
+            throw new RuntimeException(
+                ("Unable to create instance of "
+                    + rawType
+                    + ". Registering an InstanceCreator or a TypeAdapter for this type, or adding a"
+                    + " no-args constructor may fix this problem."),
+                e);
           }
         }
       };
     } else {
-      String exceptionMessage = "Unable to create instance of " + rawType + "; usage of JDK Unsafe"
-          + " is disabled. Registering an InstanceCreator or a TypeAdapter for this type, adding a no-args"
-          + " constructor, or enabling usage of JDK Unsafe may fix this problem.";
+      String exceptionMessage =
+          "Unable to create instance of "
+              + rawType
+              + "; usage of JDK Unsafe is disabled. Registering an InstanceCreator or a TypeAdapter"
+              + " for this type, adding a no-args constructor, or enabling usage of JDK Unsafe may"
+              + " fix this problem.";
 
       // Check if R8 removed all constructors
       if (rawType.getDeclaredConstructors().length == 0) {
-        // R8 with Unsafe disabled might not be common enough to warrant a separate Troubleshooting Guide entry
-        exceptionMessage += " Or adjust your R8 configuration to keep the no-args constructor of the class.";
+        // R8 with Unsafe disabled might not be common enough to warrant a separate Troubleshooting
+        // Guide entry
+        exceptionMessage +=
+            " Or adjust your R8 configuration to keep the no-args constructor of the class.";
       }
 
       // Explicit final variable to allow usage in the anonymous class below
       final String exceptionMessageF = exceptionMessage;
 
       return new ObjectConstructor<T>() {
-        @Override public T construct() {
+        @Override
+        public T construct() {
           throw new JsonIOException(exceptionMessageF);
         }
       };
     }
   }
 
-  @Override public String toString() {
+  @Override
+  public String toString() {
     return instanceCreators.toString();
   }
 }

gson/src/main/java/com/google/gson/internal/Excluder.java

@@ -24,6 +24,7 @@ import com.google.gson.TypeAdapterFactory;
 import com.google.gson.annotations.Expose;
 import com.google.gson.annotations.Since;
 import com.google.gson.annotations.Until;
+import com.google.gson.internal.reflect.ReflectionHelper;
 import com.google.gson.reflect.TypeToken;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
@@ -35,14 +36,12 @@ import java.util.Collections;
 import java.util.List;
 
 /**
- * This class selects which fields and types to omit. It is configurable,
- * supporting version attributes {@link Since} and {@link Until}, modifiers,
- * synthetic fields, anonymous and local classes, inner classes, and fields with
- * the {@link Expose} annotation.
+ * This class selects which fields and types to omit. It is configurable, supporting version
+ * attributes {@link Since} and {@link Until}, modifiers, synthetic fields, anonymous and local
+ * classes, inner classes, and fields with the {@link Expose} annotation.
  *
- * <p>This class is a type adapter factory; types that are excluded will be
- * adapted to null. It may delegate to another type adapter if only one
- * direction is excluded.
+ * <p>This class is a type adapter factory; types that are excluded will be adapted to null. It may
+ * delegate to another type adapter if only one direction is excluded.
  *
  * @author Joel Leitch
  * @author Jesse Wilson
@@ -58,7 +57,8 @@ public final class Excluder implements TypeAdapterFactory, Cloneable {
   private List<ExclusionStrategy> serializationStrategies = Collections.emptyList();
   private List<ExclusionStrategy> deserializationStrategies = Collections.emptyList();
 
-  @Override protected Excluder clone() {
+  @Override
+  protected Excluder clone() {
     try {
       return (Excluder) super.clone();
     } catch (CloneNotSupportedException e) {
@@ -93,8 +93,8 @@ public final class Excluder implements TypeAdapterFactory, Cloneable {
     return result;
   }
 
-  public Excluder withExclusionStrategy(ExclusionStrategy exclusionStrategy,
-      boolean serialization, boolean deserialization) {
+  public Excluder withExclusionStrategy(
+      ExclusionStrategy exclusionStrategy, boolean serialization, boolean deserialization) {
     Excluder result = clone();
     if (serialization) {
       result.serializationStrategies = new ArrayList<>(serializationStrategies);
@@ -107,22 +107,26 @@ public final class Excluder implements TypeAdapterFactory, Cloneable {
     return result;
   }
 
-  @Override public <T> TypeAdapter<T> create(final Gson gson, final TypeToken<T> type) {
+  @Override
+  public <T> TypeAdapter<T> create(final Gson gson, final TypeToken<T> type) {
     Class<?> rawType = type.getRawType();
-    boolean excludeClass = excludeClassChecks(rawType);
 
-    final boolean skipSerialize = excludeClass || excludeClassInStrategy(rawType, true);
-    final boolean skipDeserialize = excludeClass ||  excludeClassInStrategy(rawType, false);
+    final boolean skipSerialize = excludeClass(rawType, true);
+    final boolean skipDeserialize = excludeClass(rawType, false);
 
     if (!skipSerialize && !skipDeserialize) {
       return null;
     }
 
     return new TypeAdapter<T>() {
-      /** The delegate is lazily created because it may not be needed, and creating it may fail. */
-      private TypeAdapter<T> delegate;
+      /**
+       * The delegate is lazily created because it may not be needed, and creating it may fail.
+       * Field has to be {@code volatile} because {@link Gson} guarantees to be thread-safe.
+       */
+      private volatile TypeAdapter<T> delegate;
 
-      @Override public T read(JsonReader in) throws IOException {
+      @Override
+      public T read(JsonReader in) throws IOException {
         if (skipDeserialize) {
           in.skipValue();
           return null;
@@ -130,7 +134,8 @@ public final class Excluder implements TypeAdapterFactory, Cloneable {
         return delegate().read(in);
       }
 
-      @Override public void write(JsonWriter out, T value) throws IOException {
+      @Override
+      public void write(JsonWriter out, T value) throws IOException {
         if (skipSerialize) {
           out.nullValue();
           return;
@@ -139,10 +144,10 @@ public final class Excluder implements TypeAdapterFactory, Cloneable {
       }
 
       private TypeAdapter<T> delegate() {
+        // A race might lead to `delegate` being assigned by multiple threads but the last
+        // assignment will stick
         TypeAdapter<T> d = delegate;
-        return d != null
-            ? d
-            : (delegate = gson.getDelegateAdapter(Excluder.this, type));
+        return d != null ? d : (delegate = gson.getDelegateAdapter(Excluder.this, type));
       }
     };
   }
@@ -168,11 +173,7 @@ public final class Excluder implements TypeAdapterFactory, Cloneable {
       }
     }
 
-    if (!serializeInnerClasses && isInnerClass(field.getType())) {
-      return true;
-    }
-
-    if (isAnonymousOrNonStaticLocal(field.getType())) {
+    if (excludeClass(field.getType(), serialize)) {
       return true;
     }
 
@@ -189,44 +190,46 @@ public final class Excluder implements TypeAdapterFactory, Cloneable {
     return false;
   }
 
-  private boolean excludeClassChecks(Class<?> clazz) {
-      if (version != Excluder.IGNORE_VERSIONS && !isValidVersion(clazz.getAnnotation(Since.class), clazz.getAnnotation(Until.class))) {
-          return true;
-      }
-
-      if (!serializeInnerClasses && isInnerClass(clazz)) {
-          return true;
-      }
-
-      return isAnonymousOrNonStaticLocal(clazz);
-  }
-
+  // public for unit tests; can otherwise be private
   public boolean excludeClass(Class<?> clazz, boolean serialize) {
-      return excludeClassChecks(clazz) ||
-              excludeClassInStrategy(clazz, serialize);
-  }
+    if (version != Excluder.IGNORE_VERSIONS
+        && !isValidVersion(clazz.getAnnotation(Since.class), clazz.getAnnotation(Until.class))) {
+      return true;
+    }
 
-  private boolean excludeClassInStrategy(Class<?> clazz, boolean serialize) {
-      List<ExclusionStrategy> list = serialize ? serializationStrategies : deserializationStrategies;
-      for (ExclusionStrategy exclusionStrategy : list) {
-          if (exclusionStrategy.shouldSkipClass(clazz)) {
-              return true;
-          }
+    if (!serializeInnerClasses && isInnerClass(clazz)) {
+      return true;
+    }
+
+    /*
+     * Exclude anonymous and local classes because they can have synthetic fields capturing enclosing
+     * values which makes serialization and deserialization unreliable.
+     * Don't exclude anonymous enum subclasses because enum types have a built-in adapter.
+     *
+     * Exclude only for deserialization; for serialization allow because custom adapter might be
+     * used; if no custom adapter exists reflection-based adapter otherwise excludes value.
+     *
+     * Cannot allow deserialization reliably here because some custom adapters like Collection adapter
+     * fall back to creating instances using Unsafe, which would likely lead to runtime exceptions
+     * for anonymous and local classes if they capture values.
+     */
+    if (!serialize
+        && !Enum.class.isAssignableFrom(clazz)
+        && ReflectionHelper.isAnonymousOrNonStaticLocal(clazz)) {
+      return true;
+    }
+
+    List<ExclusionStrategy> list = serialize ? serializationStrategies : deserializationStrategies;
+    for (ExclusionStrategy exclusionStrategy : list) {
+      if (exclusionStrategy.shouldSkipClass(clazz)) {
+        return true;
       }
-      return false;
+    }
+    return false;
   }
 
-  private boolean isAnonymousOrNonStaticLocal(Class<?> clazz) {
-    return !Enum.class.isAssignableFrom(clazz) && !isStatic(clazz)
-        && (clazz.isAnonymousClass() || clazz.isLocalClass());
-  }
-
-  private boolean isInnerClass(Class<?> clazz) {
-    return clazz.isMemberClass() && !isStatic(clazz);
-  }
-
-  private boolean isStatic(Class<?> clazz) {
-    return (clazz.getModifiers() & Modifier.STATIC) != 0;
+  private static boolean isInnerClass(Class<?> clazz) {
+    return clazz.isMemberClass() && !ReflectionHelper.isStatic(clazz);
   }
 
   private boolean isValidVersion(Since since, Until until) {

gson/src/main/java/com/google/gson/internal/JavaVersion.java

@@ -16,33 +16,33 @@
 
 package com.google.gson.internal;
 
-/**
- * Utility to check the major Java version of the current JVM.
- */
+/** Utility to check the major Java version of the current JVM. */
 public final class JavaVersion {
-  // Oracle defines naming conventions at http://www.oracle.com/technetwork/java/javase/versioning-naming-139433.html
-  // However, many alternate implementations differ. For example, Debian used 9-debian as the version string
+  // Oracle defines naming conventions at
+  // http://www.oracle.com/technetwork/java/javase/versioning-naming-139433.html
+  // However, many alternate implementations differ. For example, Debian used 9-debian as the
+  // version string
 
   private static final int majorJavaVersion = determineMajorJavaVersion();
 
   private static int determineMajorJavaVersion() {
     String javaVersion = System.getProperty("java.version");
-    return getMajorJavaVersion(javaVersion);
+    return parseMajorJavaVersion(javaVersion);
   }
 
   // Visible for testing only
-  static int getMajorJavaVersion(String javaVersion) {
+  static int parseMajorJavaVersion(String javaVersion) {
     int version = parseDotted(javaVersion);
     if (version == -1) {
       version = extractBeginningInt(javaVersion);
     }
     if (version == -1) {
-      return 6;  // Choose minimum supported JDK version as default
+      return 6; // Choose minimum supported JDK version as default
     }
     return version;
   }
 
-  // Parses both legacy 1.8 style and newer 9.0.4 style 
+  // Parses both legacy 1.8 style and newer 9.0.4 style
   private static int parseDotted(String javaVersion) {
     try {
       String[] parts = javaVersion.split("[._]", 3);
@@ -86,11 +86,12 @@ public final class JavaVersion {
   /**
    * Gets a boolean value depending if the application is running on Java 9 or later
    *
-   * @return {@code true} if the application is running on Java 9 or later; and {@code false} otherwise.
+   * @return {@code true} if the application is running on Java 9 or later; and {@code false}
+   *     otherwise.
    */
   public static boolean isJava9OrLater() {
     return majorJavaVersion >= 9;
   }
 
-  private JavaVersion() { }
+  private JavaVersion() {}
 }

gson/src/main/java/com/google/gson/internal/JsonReaderInternalAccess.java

@@ -19,14 +19,13 @@ package com.google.gson.internal;
 import com.google.gson.stream.JsonReader;
 import java.io.IOException;
 
-/**
- * Internal-only APIs of JsonReader available only to other classes in Gson.
- */
+/** Internal-only APIs of JsonReader available only to other classes in Gson. */
 public abstract class JsonReaderInternalAccess {
-  public static JsonReaderInternalAccess INSTANCE;
+  // Suppress warnings because field is initialized by `JsonReader` class during class loading
+  // (and therefore should be thread-safe), and any usage appears after `JsonReader` was loaded
+  @SuppressWarnings({"ConstantField", "NonFinalStaticField"})
+  public static volatile JsonReaderInternalAccess INSTANCE;
 
-  /**
-   * Changes the type of the current property name token to a string value.
-   */
+  /** Changes the type of the current property name token to a string value. */
   public abstract void promoteNameToValue(JsonReader reader) throws IOException;
 }

gson/src/main/java/com/google/gson/internal/LazilyParsedNumber.java

@@ -30,11 +30,17 @@ import java.math.BigDecimal;
 public final class LazilyParsedNumber extends Number {
   private final String value;
 
-  /** @param value must not be null */
+  /**
+   * @param value must not be null
+   */
   public LazilyParsedNumber(String value) {
     this.value = value;
   }
 
+  private BigDecimal asBigDecimal() {
+    return NumberLimits.parseBigDecimal(value);
+  }
+
   @Override
   public int intValue() {
     try {
@@ -43,7 +49,7 @@ public final class LazilyParsedNumber extends Number {
       try {
         return (int) Long.parseLong(value);
       } catch (NumberFormatException nfe) {
-        return new BigDecimal(value).intValue();
+        return asBigDecimal().intValue();
       }
     }
   }
@@ -53,7 +59,7 @@ public final class LazilyParsedNumber extends Number {
     try {
       return Long.parseLong(value);
     } catch (NumberFormatException e) {
-      return new BigDecimal(value).longValue();
+      return asBigDecimal().longValue();
     }
   }
 
@@ -73,16 +79,16 @@ public final class LazilyParsedNumber extends Number {
   }
 
   /**
-   * If somebody is unlucky enough to have to serialize one of these, serialize
-   * it as a BigDecimal so that they won't need Gson on the other side to
-   * deserialize it.
+   * If somebody is unlucky enough to have to serialize one of these, serialize it as a BigDecimal
+   * so that they won't need Gson on the other side to deserialize it.
    */
   private Object writeReplace() throws ObjectStreamException {
-    return new BigDecimal(value);
+    return asBigDecimal();
   }
 
   private void readObject(ObjectInputStream in) throws IOException {
-    // Don't permit directly deserializing this class; writeReplace() should have written a replacement
+    // Don't permit directly deserializing this class; writeReplace() should have written a
+    // replacement
     throw new InvalidObjectException("Deserialization is unsupported");
   }
 

gson/src/main/java/com/google/gson/internal/LinkedTreeMap.java

@@ -29,24 +29,26 @@ import java.util.ConcurrentModificationException;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.NoSuchElementException;
-import java.util.Set;
 import java.util.Objects;
+import java.util.Set;
 
 /**
- * A map of comparable keys to values. Unlike {@code TreeMap}, this class uses
- * insertion order for iteration order. Comparison order is only used as an
- * optimization for efficient insertion and removal.
+ * A map of comparable keys to values. Unlike {@code TreeMap}, this class uses insertion order for
+ * iteration order. Comparison order is only used as an optimization for efficient insertion and
+ * removal.
  *
  * <p>This implementation was derived from Android 4.1's TreeMap class.
  */
 @SuppressWarnings("serial") // ignore warning about missing serialVersionUID
 public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Serializable {
-  @SuppressWarnings({ "unchecked", "rawtypes" }) // to avoid Comparable<Comparable<Comparable<...>>>
-  private static final Comparator<Comparable> NATURAL_ORDER = new Comparator<Comparable>() {
-    @Override public int compare(Comparable a, Comparable b) {
-      return a.compareTo(b);
-    }
-  };
+  @SuppressWarnings({"unchecked", "rawtypes"}) // to avoid Comparable<Comparable<Comparable<...>>>
+  private static final Comparator<Comparable> NATURAL_ORDER =
+      new Comparator<Comparable>() {
+        @Override
+        public int compare(Comparable a, Comparable b) {
+          return a.compareTo(b);
+        }
+      };
 
   private final Comparator<? super K> comparator;
   private final boolean allowNullValues;
@@ -58,8 +60,8 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
   final Node<K, V> header;
 
   /**
-   * Create a natural order, empty tree map whose keys must be mutually
-   * comparable and non-null, and whose values can be {@code null}.
+   * Create a natural order, empty tree map whose keys must be mutually comparable and non-null, and
+   * whose values can be {@code null}.
    */
   @SuppressWarnings("unchecked") // unsafe! this assumes K is comparable
   public LinkedTreeMap() {
@@ -67,8 +69,7 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
   }
 
   /**
-   * Create a natural order, empty tree map whose keys must be mutually
-   * comparable and non-null.
+   * Create a natural order, empty tree map whose keys must be mutually comparable and non-null.
    *
    * @param allowNullValues whether {@code null} is allowed as entry value
    */
@@ -78,36 +79,39 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
   }
 
   /**
-   * Create a tree map ordered by {@code comparator}. This map's keys may only
-   * be null if {@code comparator} permits.
+   * Create a tree map ordered by {@code comparator}. This map's keys may only be null if {@code
+   * comparator} permits.
    *
-   * @param comparator the comparator to order elements with, or {@code null} to
-   *     use the natural ordering.
+   * @param comparator the comparator to order elements with, or {@code null} to use the natural
+   *     ordering.
    * @param allowNullValues whether {@code null} is allowed as entry value
    */
-  @SuppressWarnings({ "unchecked", "rawtypes" }) // unsafe! if comparator is null, this assumes K is comparable
+  // unsafe! if comparator is null, this assumes K is comparable
+  @SuppressWarnings({"unchecked", "rawtypes"})
   public LinkedTreeMap(Comparator<? super K> comparator, boolean allowNullValues) {
-    this.comparator = comparator != null
-        ? comparator
-        : (Comparator) NATURAL_ORDER;
+    this.comparator = comparator != null ? comparator : (Comparator) NATURAL_ORDER;
     this.allowNullValues = allowNullValues;
     this.header = new Node<>(allowNullValues);
   }
 
-  @Override public int size() {
+  @Override
+  public int size() {
     return size;
   }
 
-  @Override public V get(Object key) {
+  @Override
+  public V get(Object key) {
     Node<K, V> node = findByObject(key);
     return node != null ? node.value : null;
   }
 
-  @Override public boolean containsKey(Object key) {
+  @Override
+  public boolean containsKey(Object key) {
     return findByObject(key) != null;
   }
 
-  @Override public V put(K key, V value) {
+  @Override
+  public V put(K key, V value) {
     if (key == null) {
       throw new NullPointerException("key == null");
     }
@@ -120,7 +124,8 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     return result;
   }
 
-  @Override public void clear() {
+  @Override
+  public void clear() {
     root = null;
     size = 0;
     modCount++;
@@ -130,7 +135,8 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     header.next = header.prev = header;
   }
 
-  @Override public V remove(Object key) {
+  @Override
+  public V remove(Object key) {
     Node<K, V> node = removeInternalByKey(key);
     return node != null ? node.value : null;
   }
@@ -138,8 +144,7 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
   /**
    * Returns the node at or adjacent to the given key, creating it if requested.
    *
-   * @throws ClassCastException if {@code key} and the tree's keys aren't
-   *     mutually comparable.
+   * @throws ClassCastException if {@code key} and the tree's keys aren't mutually comparable.
    */
   Node<K, V> find(K key, boolean create) {
     Comparator<? super K> comparator = this.comparator;
@@ -149,14 +154,14 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     if (nearest != null) {
       // Micro-optimization: avoid polymorphic calls to Comparator.compare().
       @SuppressWarnings("unchecked") // Throws a ClassCastException below if there's trouble.
-          Comparable<Object> comparableKey = (comparator == NATURAL_ORDER)
-          ? (Comparable<Object>) key
-          : null;
+      Comparable<Object> comparableKey =
+          (comparator == NATURAL_ORDER) ? (Comparable<Object>) key : null;
 
       while (true) {
-        comparison = (comparableKey != null)
-            ? comparableKey.compareTo(nearest.key)
-            : comparator.compare(key, nearest.key);
+        comparison =
+            (comparableKey != null)
+                ? comparableKey.compareTo(nearest.key)
+                : comparator.compare(key, nearest.key);
 
         // We found the requested key.
         if (comparison == 0) {
@@ -213,13 +218,12 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
   }
 
   /**
-   * Returns this map's entry that has the same key and value as {@code
-   * entry}, or null if this map has no such entry.
+   * Returns this map's entry that has the same key and value as {@code entry}, or null if this map
+   * has no such entry.
    *
-   * <p>This method uses the comparator for key equality rather than {@code
-   * equals}. If this map's comparator isn't consistent with equals (such as
-   * {@code String.CASE_INSENSITIVE_ORDER}), then {@code remove()} and {@code
-   * contains()} will violate the collections API.
+   * <p>This method uses the comparator for key equality rather than {@code equals}. If this map's
+   * comparator isn't consistent with equals (such as {@code String.CASE_INSENSITIVE_ORDER}), then
+   * {@code remove()} and {@code contains()} will violate the collections API.
    */
   Node<K, V> findByEntry(Entry<?, ?> entry) {
     Node<K, V> mine = findByObject(entry.getKey());
@@ -227,13 +231,12 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     return valuesEqual ? mine : null;
   }
 
-  private boolean equal(Object a, Object b) {
+  private static boolean equal(Object a, Object b) {
     return Objects.equals(a, b);
   }
 
   /**
-   * Removes {@code node} from this tree, rearranging the tree's structure as
-   * necessary.
+   * Removes {@code node} from this tree, rearranging the tree's structure as necessary.
    *
    * @param unlink true to also unlink this node from the iteration linked list.
    */
@@ -325,11 +328,10 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
   }
 
   /**
-   * Rebalances the tree by making any AVL rotations necessary between the
-   * newly-unbalanced node and the tree's root.
+   * Rebalances the tree by making any AVL rotations necessary between the newly-unbalanced node and
+   * the tree's root.
    *
-   * @param insert true if the node was unbalanced by an insert; false if it
-   *     was by a removal.
+   * @param insert true if the node was unbalanced by an insert; false if it was by a removal.
    */
   private void rebalance(Node<K, V> unbalanced, boolean insert) {
     for (Node<K, V> node = unbalanced; node != null; node = node.parent) {
@@ -391,9 +393,7 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     }
   }
 
-  /**
-   * Rotates the subtree so that its root's right child is the new root.
-   */
+  /** Rotates the subtree so that its root's right child is the new root. */
   private void rotateLeft(Node<K, V> root) {
     Node<K, V> left = root.left;
     Node<K, V> pivot = root.right;
@@ -413,15 +413,12 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     root.parent = pivot;
 
     // fix heights
-    root.height = Math.max(left != null ? left.height : 0,
-        pivotLeft != null ? pivotLeft.height : 0) + 1;
-    pivot.height = Math.max(root.height,
-        pivotRight != null ? pivotRight.height : 0) + 1;
+    root.height =
+        Math.max(left != null ? left.height : 0, pivotLeft != null ? pivotLeft.height : 0) + 1;
+    pivot.height = Math.max(root.height, pivotRight != null ? pivotRight.height : 0) + 1;
   }
 
-  /**
-   * Rotates the subtree so that its root's left child is the new root.
-   */
+  /** Rotates the subtree so that its root's left child is the new root. */
   private void rotateRight(Node<K, V> root) {
     Node<K, V> pivot = root.left;
     Node<K, V> right = root.right;
@@ -441,21 +438,22 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     root.parent = pivot;
 
     // fixup heights
-    root.height = Math.max(right != null ? right.height : 0,
-        pivotRight != null ? pivotRight.height : 0) + 1;
-    pivot.height = Math.max(root.height,
-        pivotLeft != null ? pivotLeft.height : 0) + 1;
+    root.height =
+        Math.max(right != null ? right.height : 0, pivotRight != null ? pivotRight.height : 0) + 1;
+    pivot.height = Math.max(root.height, pivotLeft != null ? pivotLeft.height : 0) + 1;
   }
 
   private EntrySet entrySet;
   private KeySet keySet;
 
-  @Override public Set<Entry<K, V>> entrySet() {
+  @Override
+  public Set<Entry<K, V>> entrySet() {
     EntrySet result = entrySet;
     return result != null ? result : (entrySet = new EntrySet());
   }
 
-  @Override public Set<K> keySet() {
+  @Override
+  public Set<K> keySet() {
     KeySet result = keySet;
     return result != null ? result : (keySet = new KeySet());
   }
@@ -490,15 +488,18 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
       next.prev = this;
     }
 
-    @Override public K getKey() {
+    @Override
+    public K getKey() {
       return key;
     }
 
-    @Override public V getValue() {
+    @Override
+    public V getValue() {
       return value;
     }
 
-    @Override public V setValue(V value) {
+    @Override
+    public V setValue(V value) {
       if (value == null && !allowNullValue) {
         throw new NullPointerException("value == null");
       }
@@ -507,7 +508,8 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
       return oldValue;
     }
 
-    @Override public boolean equals(Object o) {
+    @Override
+    public boolean equals(Object o) {
       if (o instanceof Entry) {
         Entry<?, ?> other = (Entry<?, ?>) o;
         return (key == null ? other.getKey() == null : key.equals(other.getKey()))
@@ -516,18 +518,17 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
       return false;
     }
 
-    @Override public int hashCode() {
-      return (key == null ? 0 : key.hashCode())
-          ^ (value == null ? 0 : value.hashCode());
+    @Override
+    public int hashCode() {
+      return (key == null ? 0 : key.hashCode()) ^ (value == null ? 0 : value.hashCode());
     }
 
-    @Override public String toString() {
+    @Override
+    public String toString() {
       return key + "=" + value;
     }
 
-    /**
-     * Returns the first node in this subtree.
-     */
+    /** Returns the first node in this subtree. */
     public Node<K, V> first() {
       Node<K, V> node = this;
       Node<K, V> child = node.left;
@@ -538,9 +539,7 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
       return node;
     }
 
-    /**
-     * Returns the last node in this subtree.
-     */
+    /** Returns the last node in this subtree. */
     public Node<K, V> last() {
       Node<K, V> node = this;
       Node<K, V> child = node.right;
@@ -557,8 +556,7 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
     Node<K, V> lastReturned = null;
     int expectedModCount = modCount;
 
-    LinkedTreeMapIterator() {
-    }
+    LinkedTreeMapIterator() {}
 
     @Override
     @SuppressWarnings("ReferenceEquality")
@@ -579,7 +577,8 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
       return lastReturned = e;
     }
 
-    @Override public final void remove() {
+    @Override
+    public final void remove() {
       if (lastReturned == null) {
         throw new IllegalStateException();
       }
@@ -590,23 +589,28 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
   }
 
   class EntrySet extends AbstractSet<Entry<K, V>> {
-    @Override public int size() {
+    @Override
+    public int size() {
       return size;
     }
 
-    @Override public Iterator<Entry<K, V>> iterator() {
+    @Override
+    public Iterator<Entry<K, V>> iterator() {
       return new LinkedTreeMapIterator<Entry<K, V>>() {
-        @Override public Entry<K, V> next() {
+        @Override
+        public Entry<K, V> next() {
           return nextNode();
         }
       };
     }
 
-    @Override public boolean contains(Object o) {
+    @Override
+    public boolean contains(Object o) {
       return o instanceof Entry && findByEntry((Entry<?, ?>) o) != null;
     }
 
-    @Override public boolean remove(Object o) {
+    @Override
+    public boolean remove(Object o) {
       if (!(o instanceof Entry)) {
         return false;
       }
@@ -619,49 +623,56 @@ public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Seri
       return true;
     }
 
-    @Override public void clear() {
+    @Override
+    public void clear() {
       LinkedTreeMap.this.clear();
     }
   }
 
   final class KeySet extends AbstractSet<K> {
-    @Override public int size() {
+    @Override
+    public int size() {
       return size;
     }
 
-    @Override public Iterator<K> iterator() {
+    @Override
+    public Iterator<K> iterator() {
       return new LinkedTreeMapIterator<K>() {
-        @Override public K next() {
+        @Override
+        public K next() {
           return nextNode().key;
         }
       };
     }
 
-    @Override public boolean contains(Object o) {
+    @Override
+    public boolean contains(Object o) {
       return containsKey(o);
     }
 
-    @Override public boolean remove(Object key) {
+    @Override
+    public boolean remove(Object key) {
       return removeInternalByKey(key) != null;
     }
 
-    @Override public void clear() {
+    @Override
+    public void clear() {
       LinkedTreeMap.this.clear();
     }
   }
 
   /**
-   * If somebody is unlucky enough to have to serialize one of these, serialize
-   * it as a LinkedHashMap so that they won't need Gson on the other side to
-   * deserialize it. Using serialization defeats our DoS defence, so most apps
-   * shouldn't use it.
+   * If somebody is unlucky enough to have to serialize one of these, serialize it as a
+   * LinkedHashMap so that they won't need Gson on the other side to deserialize it. Using
+   * serialization defeats our DoS defence, so most apps shouldn't use it.
    */
   private Object writeReplace() throws ObjectStreamException {
     return new LinkedHashMap<>(this);
   }
 
   private void readObject(ObjectInputStream in) throws IOException {
-    // Don't permit directly deserializing this class; writeReplace() should have written a replacement
+    // Don't permit directly deserializing this class; writeReplace() should have written a
+    // replacement
     throw new InvalidObjectException("Deserialization is unsupported");
   }
 }

gson/src/main/java/com/google/gson/internal/NonNullElementWrapperList.java

@@ -24,10 +24,9 @@ import java.util.Objects;
 import java.util.RandomAccess;
 
 /**
- * {@link List} which wraps another {@code List} but prevents insertion of
- * {@code null} elements. Methods which only perform checks with the element
- * argument (e.g. {@link #contains(Object)}) do not throw exceptions for
- * {@code null} arguments.
+ * {@link List} which wraps another {@code List} but prevents insertion of {@code null} elements.
+ * Methods which only perform checks with the element argument (e.g. {@link #contains(Object)}) do
+ * not throw exceptions for {@code null} arguments.
  */
 public class NonNullElementWrapperList<E> extends AbstractList<E> implements RandomAccess {
   // Explicitly specify ArrayList as type to guarantee that delegate implements RandomAccess
@@ -38,11 +37,13 @@ public class NonNullElementWrapperList<E> extends AbstractList<E> implements Ran
     this.delegate = Objects.requireNonNull(delegate);
   }
 
-  @Override public E get(int index) {
+  @Override
+  public E get(int index) {
     return delegate.get(index);
   }
 
-  @Override public int size() {
+  @Override
+  public int size() {
     return delegate.size();
   }
 
@@ -53,61 +54,76 @@ public class NonNullElementWrapperList<E> extends AbstractList<E> implements Ran
     return element;
   }
 
-  @Override public E set(int index, E element) {
+  @Override
+  public E set(int index, E element) {
     return delegate.set(index, nonNull(element));
   }
 
-  @Override public void add(int index, E element) {
+  @Override
+  public void add(int index, E element) {
     delegate.add(index, nonNull(element));
   }
 
-  @Override public E remove(int index) {
+  @Override
+  public E remove(int index) {
     return delegate.remove(index);
   }
 
   /* The following methods are overridden because their default implementation is inefficient */
 
-  @Override public void clear() {
+  @Override
+  public void clear() {
     delegate.clear();
   }
 
-  @Override public boolean remove(Object o) {
+  @SuppressWarnings("UngroupedOverloads") // this is intentionally ungrouped, see comment above
+  @Override
+  public boolean remove(Object o) {
     return delegate.remove(o);
   }
 
-  @Override public boolean removeAll(Collection<?> c) {
+  @Override
+  public boolean removeAll(Collection<?> c) {
     return delegate.removeAll(c);
   }
 
-  @Override public boolean retainAll(Collection<?> c) {
+  @Override
+  public boolean retainAll(Collection<?> c) {
     return delegate.retainAll(c);
   }
 
-  @Override public boolean contains(Object o) {
+  @Override
+  public boolean contains(Object o) {
     return delegate.contains(o);
   }
 
-  @Override public int indexOf(Object o) {
+  @Override
+  public int indexOf(Object o) {
     return delegate.indexOf(o);
   }
 
-  @Override public int lastIndexOf(Object o) {
+  @Override
+  public int lastIndexOf(Object o) {
     return delegate.lastIndexOf(o);
   }
 
-  @Override public Object[] toArray() {
+  @Override
+  public Object[] toArray() {
     return delegate.toArray();
   }
 
-  @Override public <T> T[] toArray(T[] a) {
+  @Override
+  public <T> T[] toArray(T[] a) {
     return delegate.toArray(a);
   }
 
-  @Override public boolean equals(Object o) {
+  @Override
+  public boolean equals(Object o) {
     return delegate.equals(o);
   }
 
-  @Override public int hashCode() {
+  @Override
+  public int hashCode() {
     return delegate.hashCode();
   }
 

gson/src/main/java/com/google/gson/internal/NumberLimits.java

@@ -0,0 +1,36 @@
+package com.google.gson.internal;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * This class enforces limits on numbers parsed from JSON to avoid potential performance problems
+ * when extremely large numbers are used.
+ */
+public class NumberLimits {
+  private NumberLimits() {}
+
+  private static final int MAX_NUMBER_STRING_LENGTH = 10_000;
+
+  private static void checkNumberStringLength(String s) {
+    if (s.length() > MAX_NUMBER_STRING_LENGTH) {
+      throw new NumberFormatException("Number string too large: " + s.substring(0, 30) + "...");
+    }
+  }
+
+  public static BigDecimal parseBigDecimal(String s) throws NumberFormatException {
+    checkNumberStringLength(s);
+    BigDecimal decimal = new BigDecimal(s);
+
+    // Cast to long to avoid issues with abs when value is Integer.MIN_VALUE
+    if (Math.abs((long) decimal.scale()) >= 10_000) {
+      throw new NumberFormatException("Number has unsupported scale: " + s);
+    }
+    return decimal;
+  }
+
+  public static BigInteger parseBigInteger(String s) throws NumberFormatException {
+    checkNumberStringLength(s);
+    return new BigInteger(s);
+  }
+}

gson/src/main/java/com/google/gson/internal/ObjectConstructor.java

@@ -17,17 +17,15 @@
 package com.google.gson.internal;
 
 /**
- * Defines a generic object construction factory.  The purpose of this class
- * is to construct a default instance of a class that can be used for object
- * navigation while deserialization from its JSON representation.
+ * Defines a generic object construction factory. The purpose of this class is to construct a
+ * default instance of a class that can be used for object navigation while deserialization from its
+ * JSON representation.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
 public interface ObjectConstructor<T> {
 
-  /**
-   * Returns a new instance.
-   */
+  /** Returns a new instance. */
   public T construct();
-}
+}

gson/src/main/java/com/google/gson/internal/PreJava9DateFormatProvider.java

@@ -19,68 +19,46 @@ import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.Locale;
 
-/**
- * Provides DateFormats for US locale with patterns which were the default ones before Java 9.
- */
+/** Provides DateFormats for US locale with patterns which were the default ones before Java 9. */
 public class PreJava9DateFormatProvider {
+  private PreJava9DateFormatProvider() {}
 
   /**
-   * Returns the same DateFormat as {@code DateFormat.getDateInstance(style, Locale.US)} in Java 8 or below.
+   * Returns the same DateFormat as {@code DateFormat.getDateTimeInstance(dateStyle, timeStyle,
+   * Locale.US)} in Java 8 or below.
    */
-  public static DateFormat getUSDateFormat(int style) {
-    return new SimpleDateFormat(getDateFormatPattern(style), Locale.US);
-  }
-
-  /**
-   * Returns the same DateFormat as {@code DateFormat.getDateTimeInstance(dateStyle, timeStyle, Locale.US)}
-   * in Java 8 or below.
-   */
-  public static DateFormat getUSDateTimeFormat(int dateStyle, int timeStyle) {
-    String pattern = getDatePartOfDateTimePattern(dateStyle) + " " + getTimePartOfDateTimePattern(timeStyle);
+  public static DateFormat getUsDateTimeFormat(int dateStyle, int timeStyle) {
+    String pattern =
+        getDatePartOfDateTimePattern(dateStyle) + " " + getTimePartOfDateTimePattern(timeStyle);
     return new SimpleDateFormat(pattern, Locale.US);
   }
 
-  private static String getDateFormatPattern(int style) {
-    switch (style) {
-    case DateFormat.SHORT:
-      return "M/d/yy";
-    case DateFormat.MEDIUM:
-      return "MMM d, y";
-    case DateFormat.LONG:
-      return "MMMM d, y";
-    case DateFormat.FULL:
-      return "EEEE, MMMM d, y";
-    default:
-      throw new IllegalArgumentException("Unknown DateFormat style: " + style);
-    }
-  }
-
   private static String getDatePartOfDateTimePattern(int dateStyle) {
     switch (dateStyle) {
-    case DateFormat.SHORT:
-      return "M/d/yy";
-    case DateFormat.MEDIUM:
-      return "MMM d, yyyy";
-    case DateFormat.LONG:
-      return "MMMM d, yyyy";
-    case DateFormat.FULL:
-      return "EEEE, MMMM d, yyyy";
-    default:
-      throw new IllegalArgumentException("Unknown DateFormat style: " + dateStyle);
+      case DateFormat.SHORT:
+        return "M/d/yy";
+      case DateFormat.MEDIUM:
+        return "MMM d, yyyy";
+      case DateFormat.LONG:
+        return "MMMM d, yyyy";
+      case DateFormat.FULL:
+        return "EEEE, MMMM d, yyyy";
+      default:
+        throw new IllegalArgumentException("Unknown DateFormat style: " + dateStyle);
     }
   }
 
   private static String getTimePartOfDateTimePattern(int timeStyle) {
     switch (timeStyle) {
-    case DateFormat.SHORT:
-      return "h:mm a";
-    case DateFormat.MEDIUM:
-      return "h:mm:ss a";
-    case DateFormat.FULL:
-    case DateFormat.LONG:
-      return "h:mm:ss a z";
-    default:
-      throw new IllegalArgumentException("Unknown DateFormat style: " + timeStyle);
+      case DateFormat.SHORT:
+        return "h:mm a";
+      case DateFormat.MEDIUM:
+        return "h:mm:ss a";
+      case DateFormat.FULL:
+      case DateFormat.LONG:
+        return "h:mm:ss a z";
+      default:
+        throw new IllegalArgumentException("Unknown DateFormat style: " + timeStyle);
     }
   }
 }

gson/src/main/java/com/google/gson/internal/Primitives.java

@@ -19,24 +19,22 @@ package com.google.gson.internal;
 import java.lang.reflect.Type;
 
 /**
- * Contains static utility methods pertaining to primitive types and their
- * corresponding wrapper types.
+ * Contains static utility methods pertaining to primitive types and their corresponding wrapper
+ * types.
  *
  * @author Kevin Bourrillion
  */
 public final class Primitives {
   private Primitives() {}
 
-  /**
-   * Returns true if this type is a primitive.
-   */
+  /** Returns true if this type is a primitive. */
   public static boolean isPrimitive(Type type) {
     return type instanceof Class<?> && ((Class<?>) type).isPrimitive();
   }
 
   /**
-   * Returns {@code true} if {@code type} is one of the nine
-   * primitive-wrapper types, such as {@link Integer}.
+   * Returns {@code true} if {@code type} is one of the nine primitive-wrapper types, such as {@link
+   * Integer}.
    *
    * @see Class#isPrimitive
    */
@@ -53,15 +51,16 @@ public final class Primitives {
   }
 
   /**
-   * Returns the corresponding wrapper type of {@code type} if it is a primitive
-   * type; otherwise returns {@code type} itself. Idempotent.
+   * Returns the corresponding wrapper type of {@code type} if it is a primitive type; otherwise
+   * returns {@code type} itself. Idempotent.
+   *
    * <pre>
    *     wrap(int.class) == Integer.class
    *     wrap(Integer.class) == Integer.class
    *     wrap(String.class) == String.class
    * </pre>
    */
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({"unchecked", "MissingBraces"})
   public static <T> Class<T> wrap(Class<T> type) {
     if (type == int.class) return (Class<T>) Integer.class;
     if (type == float.class) return (Class<T>) Float.class;
@@ -76,15 +75,16 @@ public final class Primitives {
   }
 
   /**
-   * Returns the corresponding primitive type of {@code type} if it is a
-   * wrapper type; otherwise returns {@code type} itself. Idempotent.
+   * Returns the corresponding primitive type of {@code type} if it is a wrapper type; otherwise
+   * returns {@code type} itself. Idempotent.
+   *
    * <pre>
    *     unwrap(Integer.class) == int.class
    *     unwrap(int.class) == int.class
    *     unwrap(String.class) == String.class
    * </pre>
    */
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({"unchecked", "MissingBraces"})
   public static <T> Class<T> unwrap(Class<T> type) {
     if (type == Integer.class) return (Class<T>) int.class;
     if (type == Float.class) return (Class<T>) float.class;

gson/src/main/java/com/google/gson/internal/ReflectionAccessFilterHelper.java

@@ -16,21 +16,19 @@
 
 package com.google.gson.internal;
 
+import com.google.gson.ReflectionAccessFilter;
+import com.google.gson.ReflectionAccessFilter.FilterResult;
 import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Method;
 import java.util.List;
 
-import com.google.gson.ReflectionAccessFilter;
-import com.google.gson.ReflectionAccessFilter.FilterResult;
-
-/**
- * Internal helper class for {@link ReflectionAccessFilter}.
- */
+/** Internal helper class for {@link ReflectionAccessFilter}. */
 public class ReflectionAccessFilterHelper {
-  private ReflectionAccessFilterHelper() { }
+  private ReflectionAccessFilterHelper() {}
 
   // Platform type detection is based on Moshi's Util.isPlatformType(Class)
-  // See https://github.com/square/moshi/blob/3c108919ee1cce88a433ffda04eeeddc0341eae7/moshi/src/main/java/com/squareup/moshi/internal/Util.java#L141
+  // See
+  // https://github.com/square/moshi/blob/3c108919ee1cce88a433ffda04eeeddc0341eae7/moshi/src/main/java/com/squareup/moshi/internal/Util.java#L141
 
   public static boolean isJavaType(Class<?> c) {
     return isJavaType(c.getName());
@@ -53,17 +51,18 @@ public class ReflectionAccessFilterHelper {
   public static boolean isAnyPlatformType(Class<?> c) {
     String className = c.getName();
     return isAndroidType(className) // Covers Android and Java
-      || className.startsWith("kotlin.")
-      || className.startsWith("kotlinx.")
-      || className.startsWith("scala.");
+        || className.startsWith("kotlin.")
+        || className.startsWith("kotlinx.")
+        || className.startsWith("scala.");
   }
 
   /**
-   * Gets the result of applying all filters until the first one returns a result
-   * other than {@link FilterResult#INDECISIVE}, or {@link FilterResult#ALLOW} if
-   * the list of filters is empty or all returned {@code INDECISIVE}.
+   * Gets the result of applying all filters until the first one returns a result other than {@link
+   * FilterResult#INDECISIVE}, or {@link FilterResult#ALLOW} if the list of filters is empty or all
+   * returned {@code INDECISIVE}.
    */
-  public static FilterResult getFilterResult(List<ReflectionAccessFilter> reflectionFilters, Class<?> c) {
+  public static FilterResult getFilterResult(
+      List<ReflectionAccessFilter> reflectionFilters, Class<?> c) {
     for (ReflectionAccessFilter filter : reflectionFilters) {
       FilterResult result = filter.check(c);
       if (result != FilterResult.INDECISIVE) {
@@ -73,42 +72,46 @@ public class ReflectionAccessFilterHelper {
     return FilterResult.ALLOW;
   }
 
-  /**
-   * See {@link AccessibleObject#canAccess(Object)} (Java >= 9)
-   */
+  /** See {@link AccessibleObject#canAccess(Object)} (Java >= 9) */
   public static boolean canAccess(AccessibleObject accessibleObject, Object object) {
     return AccessChecker.INSTANCE.canAccess(accessibleObject, object);
   }
 
-  private static abstract class AccessChecker {
+  private abstract static class AccessChecker {
     public static final AccessChecker INSTANCE;
+
     static {
       AccessChecker accessChecker = null;
       // TODO: Ideally should use Multi-Release JAR for this version specific code
       if (JavaVersion.isJava9OrLater()) {
         try {
-          final Method canAccessMethod = AccessibleObject.class.getDeclaredMethod("canAccess", Object.class);
-          accessChecker = new AccessChecker() {
-            @Override public boolean canAccess(AccessibleObject accessibleObject, Object object) {
-              try {
-                return (Boolean) canAccessMethod.invoke(accessibleObject, object);
-              } catch (Exception e) {
-                throw new RuntimeException("Failed invoking canAccess", e);
-              }
-            }
-          };
+          final Method canAccessMethod =
+              AccessibleObject.class.getDeclaredMethod("canAccess", Object.class);
+          accessChecker =
+              new AccessChecker() {
+                @Override
+                public boolean canAccess(AccessibleObject accessibleObject, Object object) {
+                  try {
+                    return (Boolean) canAccessMethod.invoke(accessibleObject, object);
+                  } catch (Exception e) {
+                    throw new RuntimeException("Failed invoking canAccess", e);
+                  }
+                }
+              };
         } catch (NoSuchMethodException ignored) {
           // OK: will assume everything is accessible
         }
       }
 
       if (accessChecker == null) {
-        accessChecker = new AccessChecker() {
-          @Override public boolean canAccess(AccessibleObject accessibleObject, Object object) {
-            // Cannot determine whether object can be accessed, so assume it can be accessed
-            return true;
-          }
-        };
+        accessChecker =
+            new AccessChecker() {
+              @Override
+              public boolean canAccess(AccessibleObject accessibleObject, Object object) {
+                // Cannot determine whether object can be accessed, so assume it can be accessed
+                return true;
+              }
+            };
       }
       INSTANCE = accessChecker;
     }

gson/src/main/java/com/google/gson/internal/Streams.java

@@ -31,17 +31,13 @@ import java.io.IOException;
 import java.io.Writer;
 import java.util.Objects;
 
-/**
- * Reads and writes GSON parse trees over streams.
- */
+/** Reads and writes GSON parse trees over streams. */
 public final class Streams {
   private Streams() {
     throw new UnsupportedOperationException();
   }
 
-  /**
-   * Takes a reader in any state and returns the next value as a JsonElement.
-   */
+  /** Takes a reader in any state and returns the next value as a JsonElement. */
   public static JsonElement parse(JsonReader reader) throws JsonParseException {
     boolean isEmpty = true;
     try {
@@ -67,9 +63,7 @@ public final class Streams {
     }
   }
 
-  /**
-   * Writes the JSON element to the writer, recursively.
-   */
+  /** Writes the JSON element to the writer, recursively. */
   public static void write(JsonElement element, JsonWriter writer) throws IOException {
     TypeAdapters.JSON_ELEMENT.write(writer, element);
   }
@@ -78,10 +72,7 @@ public final class Streams {
     return appendable instanceof Writer ? (Writer) appendable : new AppendableWriter(appendable);
   }
 
-  /**
-   * Adapts an {@link Appendable} so it can be passed anywhere a {@link Writer}
-   * is used.
-   */
+  /** Adapts an {@link Appendable} so it can be passed anywhere a {@link Writer} is used. */
   private static final class AppendableWriter extends Writer {
     private final Appendable appendable;
     private final CurrentWrite currentWrite = new CurrentWrite();
@@ -90,40 +81,47 @@ public final class Streams {
       this.appendable = appendable;
     }
 
-    @Override public void write(char[] chars, int offset, int length) throws IOException {
+    @SuppressWarnings("UngroupedOverloads") // this is intentionally ungrouped, see comment below
+    @Override
+    public void write(char[] chars, int offset, int length) throws IOException {
       currentWrite.setChars(chars);
       appendable.append(currentWrite, offset, offset + length);
     }
 
-    @Override public void flush() {}
-    @Override public void close() {}
+    @Override
+    public void flush() {}
+
+    @Override
+    public void close() {}
 
     // Override these methods for better performance
     // They would otherwise unnecessarily create Strings or char arrays
 
-    @Override public void write(int i) throws IOException {
+    @Override
+    public void write(int i) throws IOException {
       appendable.append((char) i);
     }
 
-    @Override public void write(String str, int off, int len) throws IOException {
+    @Override
+    public void write(String str, int off, int len) throws IOException {
       // Appendable.append turns null -> "null", which is not desired here
       Objects.requireNonNull(str);
       appendable.append(str, off, off + len);
     }
 
-    @Override public Writer append(CharSequence csq) throws IOException {
+    @Override
+    public Writer append(CharSequence csq) throws IOException {
       appendable.append(csq);
       return this;
     }
 
-    @Override public Writer append(CharSequence csq, int start, int end) throws IOException {
+    @Override
+    public Writer append(CharSequence csq, int start, int end) throws IOException {
       appendable.append(csq, start, end);
       return this;
     }
 
-    /**
-     * A mutable char sequence pointing at a single char[].
-     */
+    /** A mutable char sequence pointing at a single char[]. */
     private static class CurrentWrite implements CharSequence {
       private char[] chars;
       private String cachedString;
@@ -133,18 +131,24 @@ public final class Streams {
         this.cachedString = null;
       }
 
-      @Override public int length() {
+      @Override
+      public int length() {
         return chars.length;
       }
-      @Override public char charAt(int i) {
+
+      @Override
+      public char charAt(int i) {
         return chars[i];
       }
-      @Override public CharSequence subSequence(int start, int end) {
+
+      @Override
+      public CharSequence subSequence(int start, int end) {
         return new String(chars, start, end - start);
       }
 
       // Must return string representation to satisfy toString() contract
-      @Override public String toString() {
+      @Override
+      public String toString() {
         if (cachedString == null) {
           cachedString = new String(chars);
         }

gson/src/main/java/com/google/gson/internal/TroubleshootingGuide.java

@@ -3,9 +3,7 @@ package com.google.gson.internal;
 public class TroubleshootingGuide {
   private TroubleshootingGuide() {}
 
-  /**
-   * Creates a URL referring to the specified troubleshooting section.
-   */
+  /** Creates a URL referring to the specified troubleshooting section. */
   public static String createUrl(String id) {
     return "https://github.com/google/gson/blob/main/Troubleshooting.md#" + id;
   }

gson/src/main/java/com/google/gson/internal/UnsafeAllocator.java

@@ -31,14 +31,15 @@ public abstract class UnsafeAllocator {
   public abstract <T> T newInstance(Class<T> c) throws Exception;
 
   /**
-   * Asserts that the class is instantiable. This check should have already occurred
-   * in {@link ConstructorConstructor}; this check here acts as safeguard since trying
-   * to use Unsafe for non-instantiable classes might crash the JVM on some devices.
+   * Asserts that the class is instantiable. This check should have already occurred in {@link
+   * ConstructorConstructor}; this check here acts as safeguard since trying to use Unsafe for
+   * non-instantiable classes might crash the JVM on some devices.
    */
   private static void assertInstantiable(Class<?> c) {
     String exceptionMessage = ConstructorConstructor.checkInstantiable(c);
     if (exceptionMessage != null) {
-      throw new AssertionError("UnsafeAllocator is used for non-instantiable type: " + exceptionMessage);
+      throw new AssertionError(
+          "UnsafeAllocator is used for non-instantiable type: " + exceptionMessage);
     }
   }
 
@@ -73,12 +74,12 @@ public abstract class UnsafeAllocator {
     //   private static native Object newInstance(Class<?> instantiationClass, int methodId);
     // }
     try {
-      Method getConstructorId = ObjectStreamClass.class
-          .getDeclaredMethod("getConstructorId", Class.class);
+      Method getConstructorId =
+          ObjectStreamClass.class.getDeclaredMethod("getConstructorId", Class.class);
       getConstructorId.setAccessible(true);
       final int constructorId = (Integer) getConstructorId.invoke(null, Object.class);
-      final Method newInstance = ObjectStreamClass.class
-          .getDeclaredMethod("newInstance", Class.class, int.class);
+      final Method newInstance =
+          ObjectStreamClass.class.getDeclaredMethod("newInstance", Class.class, int.class);
       newInstance.setAccessible(true);
       return new UnsafeAllocator() {
         @Override
@@ -98,8 +99,8 @@ public abstract class UnsafeAllocator {
     //     Class<?> instantiationClass, Class<?> constructorClass);
     // }
     try {
-      final Method newInstance = ObjectInputStream.class
-          .getDeclaredMethod("newInstance", Class.class, Class.class);
+      final Method newInstance =
+          ObjectInputStream.class.getDeclaredMethod("newInstance", Class.class, Class.class);
       newInstance.setAccessible(true);
       return new UnsafeAllocator() {
         @Override
@@ -117,8 +118,11 @@ public abstract class UnsafeAllocator {
     return new UnsafeAllocator() {
       @Override
       public <T> T newInstance(Class<T> c) {
-        throw new UnsupportedOperationException("Cannot allocate " + c + ". Usage of JDK sun.misc.Unsafe is enabled, "
-            + "but it could not be used. Make sure your runtime is configured correctly.");
+        throw new UnsupportedOperationException(
+            "Cannot allocate "
+                + c
+                + ". Usage of JDK sun.misc.Unsafe is enabled, but it could not be used."
+                + " Make sure your runtime is configured correctly.");
       }
     };
   }

gson/src/main/java/com/google/gson/internal/bind/ArrayTypeAdapter.java

@@ -31,37 +31,41 @@ import java.lang.reflect.GenericArrayType;
 import java.lang.reflect.Type;
 import java.util.ArrayList;
 
-/**
- * Adapt an array of objects.
- */
+/** Adapt an array of objects. */
 public final class ArrayTypeAdapter<E> extends TypeAdapter<Object> {
-  public static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
-    @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
-      Type type = typeToken.getType();
-      if (!(type instanceof GenericArrayType || (type instanceof Class && ((Class<?>) type).isArray()))) {
-        return null;
-      }
+  public static final TypeAdapterFactory FACTORY =
+      new TypeAdapterFactory() {
+        @Override
+        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+          Type type = typeToken.getType();
+          if (!(type instanceof GenericArrayType
+              || (type instanceof Class && ((Class<?>) type).isArray()))) {
+            return null;
+          }
 
-      Type componentType = $Gson$Types.getArrayComponentType(type);
-      TypeAdapter<?> componentTypeAdapter = gson.getAdapter(TypeToken.get(componentType));
+          Type componentType = $Gson$Types.getArrayComponentType(type);
+          TypeAdapter<?> componentTypeAdapter = gson.getAdapter(TypeToken.get(componentType));
 
-      @SuppressWarnings({"unchecked", "rawtypes"})
-      TypeAdapter<T> arrayAdapter = new ArrayTypeAdapter(
-              gson, componentTypeAdapter, $Gson$Types.getRawType(componentType));
-      return arrayAdapter;
-    }
-  };
+          @SuppressWarnings({"unchecked", "rawtypes"})
+          TypeAdapter<T> arrayAdapter =
+              new ArrayTypeAdapter(
+                  gson, componentTypeAdapter, $Gson$Types.getRawType(componentType));
+          return arrayAdapter;
+        }
+      };
 
   private final Class<E> componentType;
   private final TypeAdapter<E> componentTypeAdapter;
 
-  public ArrayTypeAdapter(Gson context, TypeAdapter<E> componentTypeAdapter, Class<E> componentType) {
+  public ArrayTypeAdapter(
+      Gson context, TypeAdapter<E> componentTypeAdapter, Class<E> componentType) {
     this.componentTypeAdapter =
-      new TypeAdapterRuntimeTypeWrapper<>(context, componentTypeAdapter, componentType);
+        new TypeAdapterRuntimeTypeWrapper<>(context, componentTypeAdapter, componentType);
     this.componentType = componentType;
   }
 
-  @Override public Object read(JsonReader in) throws IOException {
+  @Override
+  public Object read(JsonReader in) throws IOException {
     if (in.peek() == JsonToken.NULL) {
       in.nextNull();
       return null;
@@ -98,7 +102,8 @@ public final class ArrayTypeAdapter<E> extends TypeAdapter<Object> {
     }
   }
 
-  @Override public void write(JsonWriter out, Object array) throws IOException {
+  @Override
+  public void write(JsonWriter out, Object array) throws IOException {
     if (array == null) {
       out.nullValue();
       return;

gson/src/main/java/com/google/gson/internal/bind/CollectionTypeAdapterFactory.java

@@ -31,9 +31,7 @@ import java.io.IOException;
 import java.lang.reflect.Type;
 import java.util.Collection;
 
-/**
- * Adapt a homogeneous collection of objects.
- */
+/** Adapt a homogeneous collection of objects. */
 public final class CollectionTypeAdapterFactory implements TypeAdapterFactory {
   private final ConstructorConstructor constructorConstructor;
 
@@ -63,7 +61,9 @@ public final class CollectionTypeAdapterFactory implements TypeAdapterFactory {
     private final TypeAdapter<E> elementTypeAdapter;
     private final ObjectConstructor<? extends Collection<E>> constructor;
 
-    public Adapter(Gson context, Type elementType,
+    public Adapter(
+        Gson context,
+        Type elementType,
         TypeAdapter<E> elementTypeAdapter,
         ObjectConstructor<? extends Collection<E>> constructor) {
       this.elementTypeAdapter =
@@ -71,7 +71,8 @@ public final class CollectionTypeAdapterFactory implements TypeAdapterFactory {
       this.constructor = constructor;
     }
 
-    @Override public Collection<E> read(JsonReader in) throws IOException {
+    @Override
+    public Collection<E> read(JsonReader in) throws IOException {
       if (in.peek() == JsonToken.NULL) {
         in.nextNull();
         return null;
@@ -92,7 +93,8 @@ public final class CollectionTypeAdapterFactory implements TypeAdapterFactory {
       return collection;
     }
 
-    @Override public void write(JsonWriter out, Collection<E> collection) throws IOException {
+    @Override
+    public void write(JsonWriter out, Collection<E> collection) throws IOException {
       if (collection == null) {
         out.nullValue();
         return;

gson/src/main/java/com/google/gson/internal/bind/DateTypeAdapter.java

@@ -1,109 +0,0 @@
-/*
- * Copyright (C) 2011 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.google.gson.internal.bind;
-
-import com.google.gson.Gson;
-import com.google.gson.JsonSyntaxException;
-import com.google.gson.TypeAdapter;
-import com.google.gson.TypeAdapterFactory;
-import com.google.gson.internal.JavaVersion;
-import com.google.gson.internal.PreJava9DateFormatProvider;
-import com.google.gson.util.ISO8601Utils;
-import com.google.gson.reflect.TypeToken;
-import com.google.gson.stream.JsonReader;
-import com.google.gson.stream.JsonToken;
-import com.google.gson.stream.JsonWriter;
-
-import java.io.IOException;
-import java.text.DateFormat;
-import java.text.ParseException;
-import java.text.ParsePosition;
-import java.util.ArrayList;
-import java.util.Date;
-import java.util.List;
-import java.util.Locale;
-
-/**
- * Adapter for Date. Although this class appears stateless, it is not.
- * DateFormat captures its time zone and locale when it is created, which gives
- * this class state. DateFormat isn't thread safe either, so this class has
- * to synchronize its read and write methods.
- */
-public final class DateTypeAdapter extends TypeAdapter<Date> {
-  public static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
-    @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
-    @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
-      return typeToken.getRawType() == Date.class ? (TypeAdapter<T>) new DateTypeAdapter() : null;
-    }
-  };
-
-  /**
-   * List of 1 or more different date formats used for de-serialization attempts.
-   * The first of them (default US format) is used for serialization as well.
-   */
-  private final List<DateFormat> dateFormats = new ArrayList<>();
-
-  public DateTypeAdapter() {
-    dateFormats.add(DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.US));
-    if (!Locale.getDefault().equals(Locale.US)) {
-      dateFormats.add(DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT));
-    }
-    if (JavaVersion.isJava9OrLater()) {
-      dateFormats.add(PreJava9DateFormatProvider.getUSDateTimeFormat(DateFormat.DEFAULT, DateFormat.DEFAULT));
-    }
-  }
-
-  @Override public Date read(JsonReader in) throws IOException {
-    if (in.peek() == JsonToken.NULL) {
-      in.nextNull();
-      return null;
-    }
-    return deserializeToDate(in);
-  }
-
-  private Date deserializeToDate(JsonReader in) throws IOException {
-    String s = in.nextString();
-    synchronized (dateFormats) {
-      for (DateFormat dateFormat : dateFormats) {
-        try {
-          return dateFormat.parse(s);
-        } catch (ParseException ignored) {
-          // OK: try the next format
-        }
-      }
-    }
-    try {
-      return ISO8601Utils.parse(s, new ParsePosition(0));
-    } catch (ParseException e) {
-      throw new JsonSyntaxException("Failed parsing '" + s + "' as Date; at path " + in.getPreviousPath(), e);
-    }
-  }
-
-  @Override public void write(JsonWriter out, Date value) throws IOException {
-    if (value == null) {
-      out.nullValue();
-      return;
-    }
-
-    DateFormat dateFormat = dateFormats.get(0);
-    String dateFormatAsString;
-    synchronized (dateFormats) {
-      dateFormatAsString = dateFormat.format(value);
-    }
-    out.value(dateFormatAsString);
-  }
-}

gson/src/main/java/com/google/gson/internal/bind/DefaultDateTypeAdapter.java

@@ -16,12 +16,14 @@
 
 package com.google.gson.internal.bind;
 
+import com.google.gson.Gson;
 import com.google.gson.JsonSyntaxException;
 import com.google.gson.TypeAdapter;
 import com.google.gson.TypeAdapterFactory;
 import com.google.gson.internal.JavaVersion;
 import com.google.gson.internal.PreJava9DateFormatProvider;
 import com.google.gson.util.ISO8601Utils;
+import com.google.gson.reflect.TypeToken;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonToken;
 import com.google.gson.stream.JsonWriter;
@@ -35,11 +37,17 @@ import java.util.Date;
 import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
+import java.util.TimeZone;
 
 /**
- * This type adapter supports subclasses of date by defining a
- * {@link DefaultDateTypeAdapter.DateType} and then using its {@code createAdapterFactory}
- * methods.
+ * This type adapter supports subclasses of date by defining a {@link
+ * DefaultDateTypeAdapter.DateType} and then using its {@code createAdapterFactory} methods.
+ *
+ * <p><b>Important:</b> Instances of this class (or rather the {@link SimpleDateFormat} they use)
+ * capture the current default {@link Locale} and {@link TimeZone} when they are created. Therefore
+ * avoid storing factories obtained from {@link DateType} in {@code static} fields, since they only
+ * create a single adapter instance and its behavior would then depend on when Gson classes are
+ * loaded first, and which default {@code Locale} and {@code TimeZone} was used at that point.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -47,12 +55,38 @@ import java.util.Objects;
 public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T> {
   private static final String SIMPLE_NAME = "DefaultDateTypeAdapter";
 
-  public static abstract class DateType<T extends Date> {
-    public static final DateType<Date> DATE = new DateType<Date>(Date.class) {
-      @Override protected Date deserialize(Date date) {
-        return date;
-      }
-    };
+  /** Factory for {@link Date} adapters which use {@link DateFormat#DEFAULT} as style. */
+  public static final TypeAdapterFactory DEFAULT_STYLE_FACTORY =
+      // Because SimpleDateFormat captures the default TimeZone when it was created, let the factory
+      // always create new DefaultDateTypeAdapter instances (which are then cached by the Gson
+      // instances) instead of having a single static DefaultDateTypeAdapter instance
+      // Otherwise the behavior would depend on when an application first loads Gson classes and
+      // which default TimeZone is set at that point, which would be quite brittle
+      new TypeAdapterFactory() {
+        @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
+        @Override
+        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+          return typeToken.getRawType() == Date.class
+              ? (TypeAdapter<T>)
+                  new DefaultDateTypeAdapter<>(
+                      DateType.DATE, DateFormat.DEFAULT, DateFormat.DEFAULT)
+              : null;
+        }
+
+        @Override
+        public String toString() {
+          return "DefaultDateTypeAdapter#DEFAULT_STYLE_FACTORY";
+        }
+      };
+
+  public abstract static class DateType<T extends Date> {
+    public static final DateType<Date> DATE =
+        new DateType<Date>(Date.class) {
+          @Override
+          protected Date deserialize(Date date) {
+            return date;
+          }
+        };
 
     private final Class<T> dateClass;
 
@@ -70,24 +104,16 @@ public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T>
       return createFactory(new DefaultDateTypeAdapter<>(this, datePattern));
     }
 
-    public final TypeAdapterFactory createAdapterFactory(int style) {
-      return createFactory(new DefaultDateTypeAdapter<>(this, style));
-    }
-
     public final TypeAdapterFactory createAdapterFactory(int dateStyle, int timeStyle) {
       return createFactory(new DefaultDateTypeAdapter<>(this, dateStyle, timeStyle));
     }
-
-    public final TypeAdapterFactory createDefaultsAdapterFactory() {
-      return createFactory(new DefaultDateTypeAdapter<>(this, DateFormat.DEFAULT, DateFormat.DEFAULT));
-    }
   }
 
   private final DateType<T> dateType;
 
   /**
-   * List of 1 or more different date formats used for de-serialization attempts.
-   * The first of them is used for serialization as well.
+   * List of 1 or more different date formats used for de-serialization attempts. The first of them
+   * is used for serialization as well.
    */
   private final List<DateFormat> dateFormats = new ArrayList<>();
 
@@ -99,17 +125,6 @@ public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T>
     }
   }
 
-  private DefaultDateTypeAdapter(DateType<T> dateType, int style) {
-    this.dateType = Objects.requireNonNull(dateType);
-    dateFormats.add(DateFormat.getDateInstance(style, Locale.US));
-    if (!Locale.getDefault().equals(Locale.US)) {
-      dateFormats.add(DateFormat.getDateInstance(style));
-    }
-    if (JavaVersion.isJava9OrLater()) {
-      dateFormats.add(PreJava9DateFormatProvider.getUSDateFormat(style));
-    }
-  }
-
   private DefaultDateTypeAdapter(DateType<T> dateType, int dateStyle, int timeStyle) {
     this.dateType = Objects.requireNonNull(dateType);
     dateFormats.add(DateFormat.getDateTimeInstance(dateStyle, timeStyle, Locale.US));
@@ -117,12 +132,10 @@ public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T>
       dateFormats.add(DateFormat.getDateTimeInstance(dateStyle, timeStyle));
     }
     if (JavaVersion.isJava9OrLater()) {
-      dateFormats.add(PreJava9DateFormatProvider.getUSDateTimeFormat(dateStyle, timeStyle));
+      dateFormats.add(PreJava9DateFormatProvider.getUsDateTimeFormat(dateStyle, timeStyle));
     }
   }
 
-  // These methods need to be synchronized since JDK DateFormat classes are not thread-safe
-  // See issue 162
   @Override
   public void write(JsonWriter out, Date value) throws IOException {
     if (value == null) {
@@ -132,6 +145,7 @@ public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T>
 
     DateFormat dateFormat = dateFormats.get(0);
     String dateFormatAsString;
+    // Needs to be synchronized since JDK DateFormat classes are not thread-safe
     synchronized (dateFormats) {
       dateFormatAsString = dateFormat.format(value);
     }
@@ -150,12 +164,16 @@ public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T>
 
   private Date deserializeToDate(JsonReader in) throws IOException {
     String s = in.nextString();
+    // Needs to be synchronized since JDK DateFormat classes are not thread-safe
     synchronized (dateFormats) {
       for (DateFormat dateFormat : dateFormats) {
+        TimeZone originalTimeZone = dateFormat.getTimeZone();
         try {
           return dateFormat.parse(s);
         } catch (ParseException ignored) {
           // OK: try the next format
+        } finally {
+          dateFormat.setTimeZone(originalTimeZone);
         }
       }
     }
@@ -163,7 +181,8 @@ public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T>
     try {
       return ISO8601Utils.parse(s, new ParsePosition(0));
     } catch (ParseException e) {
-      throw new JsonSyntaxException("Failed parsing '" + s + "' as Date; at path " + in.getPreviousPath(), e);
+      throw new JsonSyntaxException(
+          "Failed parsing '" + s + "' as Date; at path " + in.getPreviousPath(), e);
     }
   }
 

gson/src/main/java/com/google/gson/internal/bind/JsonAdapterAnnotationTypeAdapterFactory.java

@@ -36,29 +36,26 @@ import java.util.concurrent.ConcurrentMap;
  */
 public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapterFactory {
   private static class DummyTypeAdapterFactory implements TypeAdapterFactory {
-    @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+    @Override
+    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
       throw new AssertionError("Factory should not be used");
     }
   }
 
-  /**
-   * Factory used for {@link TreeTypeAdapter}s created for {@code @JsonAdapter}
-   * on a class.
-   */
-  private static final TypeAdapterFactory TREE_TYPE_CLASS_DUMMY_FACTORY = new DummyTypeAdapterFactory();
+  /** Factory used for {@link TreeTypeAdapter}s created for {@code @JsonAdapter} on a class. */
+  private static final TypeAdapterFactory TREE_TYPE_CLASS_DUMMY_FACTORY =
+      new DummyTypeAdapterFactory();
 
-  /**
-   * Factory used for {@link TreeTypeAdapter}s created for {@code @JsonAdapter}
-   * on a field.
-   */
-  private static final TypeAdapterFactory TREE_TYPE_FIELD_DUMMY_FACTORY = new DummyTypeAdapterFactory();
+  /** Factory used for {@link TreeTypeAdapter}s created for {@code @JsonAdapter} on a field. */
+  private static final TypeAdapterFactory TREE_TYPE_FIELD_DUMMY_FACTORY =
+      new DummyTypeAdapterFactory();
 
   private final ConstructorConstructor constructorConstructor;
 
   /**
-   * For a class, if it is annotated with {@code @JsonAdapter} and refers to a {@link TypeAdapterFactory},
-   * stores the factory instance in case it has been requested already.
-   * Has to be a {@link ConcurrentMap} because {@link Gson} guarantees to be thread-safe.
+   * For a class, if it is annotated with {@code @JsonAdapter} and refers to a {@link
+   * TypeAdapterFactory}, stores the factory instance in case it has been requested already. Has to
+   * be a {@link ConcurrentMap} because {@link Gson} guarantees to be thread-safe.
    */
   // Note: In case these strong reference to TypeAdapterFactory instances are considered
   // a memory leak in the future, could consider switching to WeakReference<TypeAdapterFactory>
@@ -70,11 +67,12 @@ public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapte
   }
 
   // Separate helper method to make sure callers retrieve annotation in a consistent way
-  private JsonAdapter getAnnotation(Class<?> rawType) {
+  private static JsonAdapter getAnnotation(Class<?> rawType) {
     return rawType.getAnnotation(JsonAdapter.class);
   }
 
-  @SuppressWarnings("unchecked") // this is not safe; requires that user has specified correct adapter class for @JsonAdapter
+  // this is not safe; requires that user has specified correct adapter class for @JsonAdapter
+  @SuppressWarnings("unchecked")
   @Override
   public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> targetType) {
     Class<? super T> rawType = targetType.getRawType();
@@ -82,13 +80,16 @@ public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapte
     if (annotation == null) {
       return null;
     }
-    return (TypeAdapter<T>) getTypeAdapter(constructorConstructor, gson, targetType, annotation, true);
+    return (TypeAdapter<T>)
+        getTypeAdapter(constructorConstructor, gson, targetType, annotation, true);
   }
 
   // Separate helper method to make sure callers create adapter in a consistent way
-  private static Object createAdapter(ConstructorConstructor constructorConstructor, Class<?> adapterClass) {
-    // TODO: The exception messages created by ConstructorConstructor are currently written in the context of
-    // deserialization and for example suggest usage of TypeAdapter, which would not work for @JsonAdapter usage
+  private static Object createAdapter(
+      ConstructorConstructor constructorConstructor, Class<?> adapterClass) {
+    // TODO: The exception messages created by ConstructorConstructor are currently written in the
+    // context of deserialization and for example suggest usage of TypeAdapter, which would not work
+    // for @JsonAdapter usage
     return constructorConstructor.get(TypeToken.get(adapterClass)).construct();
   }
 
@@ -98,8 +99,12 @@ public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapte
     return existingFactory != null ? existingFactory : factory;
   }
 
-  TypeAdapter<?> getTypeAdapter(ConstructorConstructor constructorConstructor, Gson gson,
-      TypeToken<?> type, JsonAdapter annotation, boolean isClassAnnotation) {
+  TypeAdapter<?> getTypeAdapter(
+      ConstructorConstructor constructorConstructor,
+      Gson gson,
+      TypeToken<?> type,
+      JsonAdapter annotation,
+      boolean isClassAnnotation) {
     Object instance = createAdapter(constructorConstructor, annotation.value());
 
     TypeAdapter<?> typeAdapter;
@@ -115,32 +120,35 @@ public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapte
 
       typeAdapter = factory.create(gson, type);
     } else if (instance instanceof JsonSerializer || instance instanceof JsonDeserializer) {
-      JsonSerializer<?> serializer = instance instanceof JsonSerializer
-          ? (JsonSerializer<?>) instance
-          : null;
-      JsonDeserializer<?> deserializer = instance instanceof JsonDeserializer
-          ? (JsonDeserializer<?>) instance
-          : null;
+      JsonSerializer<?> serializer =
+          instance instanceof JsonSerializer ? (JsonSerializer<?>) instance : null;
+      JsonDeserializer<?> deserializer =
+          instance instanceof JsonDeserializer ? (JsonDeserializer<?>) instance : null;
 
-      // Uses dummy factory instances because TreeTypeAdapter needs a 'skipPast' factory for `Gson.getDelegateAdapter`
-      // call and has to differentiate there whether TreeTypeAdapter was created for @JsonAdapter on class or field
+      // Uses dummy factory instances because TreeTypeAdapter needs a 'skipPast' factory for
+      // `Gson.getDelegateAdapter` call and has to differentiate there whether TreeTypeAdapter was
+      // created for @JsonAdapter on class or field
       TypeAdapterFactory skipPast;
       if (isClassAnnotation) {
         skipPast = TREE_TYPE_CLASS_DUMMY_FACTORY;
       } else {
         skipPast = TREE_TYPE_FIELD_DUMMY_FACTORY;
       }
-      @SuppressWarnings({ "unchecked", "rawtypes" })
-      TypeAdapter<?> tempAdapter = new TreeTypeAdapter(serializer, deserializer, gson, type, skipPast, nullSafe);
+      @SuppressWarnings({"unchecked", "rawtypes"})
+      TypeAdapter<?> tempAdapter =
+          new TreeTypeAdapter(serializer, deserializer, gson, type, skipPast, nullSafe);
       typeAdapter = tempAdapter;
 
       // TreeTypeAdapter handles nullSafe; don't additionally call `nullSafe()`
       nullSafe = false;
     } else {
-      throw new IllegalArgumentException("Invalid attempt to bind an instance of "
-          + instance.getClass().getName() + " as a @JsonAdapter for " + type.toString()
-          + ". @JsonAdapter value must be a TypeAdapter, TypeAdapterFactory,"
-          + " JsonSerializer or JsonDeserializer.");
+      throw new IllegalArgumentException(
+          "Invalid attempt to bind an instance of "
+              + instance.getClass().getName()
+              + " as a @JsonAdapter for "
+              + type.toString()
+              + ". @JsonAdapter value must be a TypeAdapter, TypeAdapterFactory,"
+              + " JsonSerializer or JsonDeserializer.");
     }
 
     if (typeAdapter != null && nullSafe) {
@@ -173,8 +181,8 @@ public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapte
 
     // If no factory has been created for the type yet check manually for a @JsonAdapter annotation
     // which specifies a TypeAdapterFactory
-    // Otherwise behavior would not be consistent, depending on whether or not adapter had been requested
-    // before call to `isClassJsonAdapterFactory` was made
+    // Otherwise behavior would not be consistent, depending on whether or not adapter had been
+    // requested before call to `isClassJsonAdapterFactory` was made
     JsonAdapter annotation = getAnnotation(rawType);
     if (annotation == null) {
       return false;

gson/src/main/java/com/google/gson/internal/bind/MapTypeAdapterFactory.java

@@ -41,80 +41,91 @@ import java.util.Map;
  * Adapts maps to either JSON objects or JSON arrays.
  *
  * <h2>Maps as JSON objects</h2>
- * For primitive keys or when complex map key serialization is not enabled, this
- * converts Java {@link Map Maps} to JSON Objects. This requires that map keys
- * can be serialized as strings; this is insufficient for some key types. For
- * example, consider a map whose keys are points on a grid. The default JSON
- * form encodes reasonably: <pre>   {@code
- *   Map<Point, String> original = new LinkedHashMap<>();
- *   original.put(new Point(5, 6), "a");
- *   original.put(new Point(8, 8), "b");
- *   System.out.println(gson.toJson(original, type));
+ *
+ * For primitive keys or when complex map key serialization is not enabled, this converts Java
+ * {@link Map Maps} to JSON Objects. This requires that map keys can be serialized as strings; this
+ * is insufficient for some key types. For example, consider a map whose keys are points on a grid.
+ * The default JSON form encodes reasonably:
+ *
+ * <pre>{@code
+ * Map<Point, String> original = new LinkedHashMap<>();
+ * original.put(new Point(5, 6), "a");
+ * original.put(new Point(8, 8), "b");
+ * System.out.println(gson.toJson(original, type));
  * }</pre>
- * The above code prints this JSON object:<pre>   {@code
- *   {
- *     "(5,6)": "a",
- *     "(8,8)": "b"
- *   }
+ *
+ * The above code prints this JSON object:
+ *
+ * <pre>{@code
+ * {
+ *   "(5,6)": "a",
+ *   "(8,8)": "b"
+ * }
  * }</pre>
- * But GSON is unable to deserialize this value because the JSON string name is
- * just the {@link Object#toString() toString()} of the map key. Attempting to
- * convert the above JSON to an object fails with a parse exception:
+ *
+ * But GSON is unable to deserialize this value because the JSON string name is just the {@link
+ * Object#toString() toString()} of the map key. Attempting to convert the above JSON to an object
+ * fails with a parse exception:
+ *
  * <pre>com.google.gson.JsonParseException: Expecting object found: "(5,6)"
  *   at com.google.gson.JsonObjectDeserializationVisitor.visitFieldUsingCustomHandler
  *   at com.google.gson.ObjectNavigator.navigateClassFields
  *   ...</pre>
  *
  * <h2>Maps as JSON arrays</h2>
- * An alternative approach taken by this type adapter when it is required and
- * complex map key serialization is enabled is to encode maps as arrays of map
- * entries. Each map entry is a two element array containing a key and a value.
- * This approach is more flexible because any type can be used as the map's key;
- * not just strings. But it's also less portable because the receiver of such
- * JSON must be aware of the map entry convention.
+ *
+ * An alternative approach taken by this type adapter when it is required and complex map key
+ * serialization is enabled is to encode maps as arrays of map entries. Each map entry is a two
+ * element array containing a key and a value. This approach is more flexible because any type can
+ * be used as the map's key; not just strings. But it's also less portable because the receiver of
+ * such JSON must be aware of the map entry convention.
  *
  * <p>Register this adapter when you are creating your GSON instance.
- * <pre>   {@code
- *   Gson gson = new GsonBuilder()
- *     .registerTypeAdapter(Map.class, new MapAsArrayTypeAdapter())
- *     .create();
+ *
+ * <pre>{@code
+ * Gson gson = new GsonBuilder()
+ *   .registerTypeAdapter(Map.class, new MapAsArrayTypeAdapter())
+ *   .create();
  * }</pre>
- * This will change the structure of the JSON emitted by the code above. Now we
- * get an array. In this case the arrays elements are map entries:
- * <pre>   {@code
+ *
+ * This will change the structure of the JSON emitted by the code above. Now we get an array. In
+ * this case the arrays elements are map entries:
+ *
+ * <pre>{@code
+ * [
  *   [
- *     [
- *       {
- *         "x": 5,
- *         "y": 6
- *       },
- *       "a",
- *     ],
- *     [
- *       {
- *         "x": 8,
- *         "y": 8
- *       },
- *       "b"
- *     ]
+ *     {
+ *       "x": 5,
+ *       "y": 6
+ *     },
+ *     "a",
+ *   ],
+ *   [
+ *     {
+ *       "x": 8,
+ *       "y": 8
+ *     },
+ *     "b"
  *   ]
+ * ]
  * }</pre>
- * This format will serialize and deserialize just fine as long as this adapter
- * is registered.
+ *
+ * This format will serialize and deserialize just fine as long as this adapter is registered.
  */
 public final class MapTypeAdapterFactory implements TypeAdapterFactory {
   private final ConstructorConstructor constructorConstructor;
   final boolean complexMapKeySerialization;
   final boolean duplicateMapKeyDeserialization;
 
-  public MapTypeAdapterFactory(ConstructorConstructor constructorConstructor,
-      boolean complexMapKeySerialization, boolean duplicateMapKeyDeserialization) {
+  public MapTypeAdapterFactory(
+      ConstructorConstructor constructorConstructor, boolean complexMapKeySerialization, boolean duplicateMapKeyDeserialization) {
     this.constructorConstructor = constructorConstructor;
     this.complexMapKeySerialization = complexMapKeySerialization;
     this.duplicateMapKeyDeserialization = duplicateMapKeyDeserialization;
   }
 
-  @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+  @Override
+  public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
     Type type = typeToken.getType();
 
     Class<? super T> rawType = typeToken.getRawType();
@@ -129,14 +140,13 @@ public final class MapTypeAdapterFactory implements TypeAdapterFactory {
 
     @SuppressWarnings({"unchecked", "rawtypes"})
     // we don't define a type parameter for the key or value types
-    TypeAdapter<T> result = new Adapter(gson, keyAndValueTypes[0], keyAdapter,
-        keyAndValueTypes[1], valueAdapter, constructor);
+    TypeAdapter<T> result =
+        new Adapter(
+            gson, keyAndValueTypes[0], keyAdapter, keyAndValueTypes[1], valueAdapter, constructor);
     return result;
   }
 
-  /**
-   * Returns a type adapter that writes the value as a string.
-   */
+  /** Returns a type adapter that writes the value as a string. */
   private TypeAdapter<?> getKeyAdapter(Gson context, Type keyType) {
     return (keyType == boolean.class || keyType == Boolean.class)
         ? TypeAdapters.BOOLEAN_AS_STRING
@@ -148,17 +158,21 @@ public final class MapTypeAdapterFactory implements TypeAdapterFactory {
     private final TypeAdapter<V> valueTypeAdapter;
     private final ObjectConstructor<? extends Map<K, V>> constructor;
 
-    public Adapter(Gson context, Type keyType, TypeAdapter<K> keyTypeAdapter,
-        Type valueType, TypeAdapter<V> valueTypeAdapter,
+    public Adapter(
+        Gson context,
+        Type keyType,
+        TypeAdapter<K> keyTypeAdapter,
+        Type valueType,
+        TypeAdapter<V> valueTypeAdapter,
         ObjectConstructor<? extends Map<K, V>> constructor) {
-      this.keyTypeAdapter =
-        new TypeAdapterRuntimeTypeWrapper<>(context, keyTypeAdapter, keyType);
+      this.keyTypeAdapter = new TypeAdapterRuntimeTypeWrapper<>(context, keyTypeAdapter, keyType);
       this.valueTypeAdapter =
-        new TypeAdapterRuntimeTypeWrapper<>(context, valueTypeAdapter, valueType);
+          new TypeAdapterRuntimeTypeWrapper<>(context, valueTypeAdapter, valueType);
       this.constructor = constructor;
     }
 
-    @Override public Map<K, V> read(JsonReader in) throws IOException {
+    @Override
+    public Map<K, V> read(JsonReader in) throws IOException {
       JsonToken peek = in.peek();
       if (peek == JsonToken.NULL) {
         in.nextNull();
@@ -196,7 +210,8 @@ public final class MapTypeAdapterFactory implements TypeAdapterFactory {
       return map;
     }
 
-    @Override public void write(JsonWriter out, Map<K, V> map) throws IOException {
+    @Override
+    public void write(JsonWriter out, Map<K, V> map) throws IOException {
       if (map == null) {
         out.nullValue();
         return;

gson/src/main/java/com/google/gson/internal/bind/NumberTypeAdapter.java

@@ -18,25 +18,21 @@ package com.google.gson.internal.bind;
 
 import com.google.gson.Gson;
 import com.google.gson.JsonSyntaxException;
-import com.google.gson.ToNumberStrategy;
 import com.google.gson.ToNumberPolicy;
+import com.google.gson.ToNumberStrategy;
 import com.google.gson.TypeAdapter;
 import com.google.gson.TypeAdapterFactory;
 import com.google.gson.reflect.TypeToken;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonToken;
 import com.google.gson.stream.JsonWriter;
-
 import java.io.IOException;
 
-/**
- * Type adapter for {@link Number}.
- */
+/** Type adapter for {@link Number}. */
 public final class NumberTypeAdapter extends TypeAdapter<Number> {
-  /**
-   * Gson default factory using {@link ToNumberPolicy#LAZILY_PARSED_NUMBER}.
-   */
-  private static final TypeAdapterFactory LAZILY_PARSED_NUMBER_FACTORY = newFactory(ToNumberPolicy.LAZILY_PARSED_NUMBER);
+  /** Gson default factory using {@link ToNumberPolicy#LAZILY_PARSED_NUMBER}. */
+  private static final TypeAdapterFactory LAZILY_PARSED_NUMBER_FACTORY =
+      newFactory(ToNumberPolicy.LAZILY_PARSED_NUMBER);
 
   private final ToNumberStrategy toNumberStrategy;
 
@@ -48,7 +44,8 @@ public final class NumberTypeAdapter extends TypeAdapter<Number> {
     final NumberTypeAdapter adapter = new NumberTypeAdapter(toNumberStrategy);
     return new TypeAdapterFactory() {
       @SuppressWarnings("unchecked")
-      @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+      @Override
+      public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
         return type.getRawType() == Number.class ? (TypeAdapter<T>) adapter : null;
       }
     };
@@ -62,21 +59,24 @@ public final class NumberTypeAdapter extends TypeAdapter<Number> {
     }
   }
 
-  @Override public Number read(JsonReader in) throws IOException {
+  @Override
+  public Number read(JsonReader in) throws IOException {
     JsonToken jsonToken = in.peek();
     switch (jsonToken) {
-    case NULL:
-      in.nextNull();
-      return null;
-    case NUMBER:
-    case STRING:
-      return toNumberStrategy.readNumber(in);
-    default:
-      throw new JsonSyntaxException("Expecting number, got: " + jsonToken + "; at path " + in.getPath());
+      case NULL:
+        in.nextNull();
+        return null;
+      case NUMBER:
+      case STRING:
+        return toNumberStrategy.readNumber(in);
+      default:
+        throw new JsonSyntaxException(
+            "Expecting number, got: " + jsonToken + "; at path " + in.getPath());
     }
   }
 
-  @Override public void write(JsonWriter out, Number value) throws IOException {
+  @Override
+  public void write(JsonWriter out, Number value) throws IOException {
     out.value(value);
   }
 }

gson/src/main/java/com/google/gson/internal/bind/ObjectTypeAdapter.java

@@ -34,13 +34,11 @@ import java.util.List;
 import java.util.Map;
 
 /**
- * Adapts types whose static type is only 'Object'. Uses getClass() on
- * serialization and a primitive/Map/List on deserialization.
+ * Adapts types whose static type is only 'Object'. Uses getClass() on serialization and a
+ * primitive/Map/List on deserialization.
  */
 public final class ObjectTypeAdapter extends TypeAdapter<Object> {
-  /**
-   * Gson default factory using {@link ToNumberPolicy#DOUBLE}.
-   */
+  /** Gson default factory using {@link ToNumberPolicy#DOUBLE}. */
   private static final TypeAdapterFactory DOUBLE_FACTORY = newFactory(ToNumberPolicy.DOUBLE);
 
   private final Gson gson;
@@ -54,7 +52,8 @@ public final class ObjectTypeAdapter extends TypeAdapter<Object> {
   private static TypeAdapterFactory newFactory(final ToNumberStrategy toNumberStrategy) {
     return new TypeAdapterFactory() {
       @SuppressWarnings("unchecked")
-      @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+      @Override
+      public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
         if (type.getRawType() == Object.class) {
           return (TypeAdapter<T>) new ObjectTypeAdapter(gson, toNumberStrategy);
         }
@@ -72,8 +71,8 @@ public final class ObjectTypeAdapter extends TypeAdapter<Object> {
   }
 
   /**
-   * Tries to begin reading a JSON array or JSON object, returning {@code null} if
-   * the next element is neither of those.
+   * Tries to begin reading a JSON array or JSON object, returning {@code null} if the next element
+   * is neither of those.
    */
   private Object tryBeginNesting(JsonReader in, JsonToken peeked) throws IOException {
     switch (peeked) {
@@ -106,7 +105,8 @@ public final class ObjectTypeAdapter extends TypeAdapter<Object> {
     }
   }
 
-  @Override public Object read(JsonReader in) throws IOException {
+  @Override
+  public Object read(JsonReader in) throws IOException {
     // Either List or Map
     Object current;
     JsonToken peeked = in.peek();
@@ -166,7 +166,8 @@ public final class ObjectTypeAdapter extends TypeAdapter<Object> {
     }
   }
 
-  @Override public void write(JsonWriter out, Object value) throws IOException {
+  @Override
+  public void write(JsonWriter out, Object value) throws IOException {
     if (value == null) {
       out.nullValue();
       return;

gson/src/main/java/com/google/gson/internal/bind/ReflectiveTypeAdapterFactory.java

@@ -56,9 +56,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
-/**
- * Type adapter that reflects over the fields and methods of a class.
- */
+/** Type adapter that reflects over the fields and methods of a class. */
 public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
   private final ConstructorConstructor constructorConstructor;
   private final FieldNamingStrategy fieldNamingPolicy;
@@ -66,8 +64,10 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
   private final JsonAdapterAnnotationTypeAdapterFactory jsonAdapterFactory;
   private final List<ReflectionAccessFilter> reflectionFilters;
 
-  public ReflectiveTypeAdapterFactory(ConstructorConstructor constructorConstructor,
-      FieldNamingStrategy fieldNamingPolicy, Excluder excluder,
+  public ReflectiveTypeAdapterFactory(
+      ConstructorConstructor constructorConstructor,
+      FieldNamingStrategy fieldNamingPolicy,
+      Excluder excluder,
       JsonAdapterAnnotationTypeAdapterFactory jsonAdapterFactory,
       List<ReflectionAccessFilter> reflectionFilters) {
     this.constructorConstructor = constructorConstructor;
@@ -78,7 +78,7 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
   }
 
   private boolean includeField(Field f, boolean serialize) {
-    return !excluder.excludeClass(f.getType(), serialize) && !excluder.excludeField(f, serialize);
+    return !excluder.excludeField(f, serialize);
   }
 
   /** first element holds the default name */
@@ -110,40 +110,77 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
       return null; // it's a primitive!
     }
 
+    // Don't allow using reflection on anonymous and local classes because synthetic fields for
+    // captured enclosing values make this unreliable
+    if (ReflectionHelper.isAnonymousOrNonStaticLocal(raw)) {
+      // This adapter just serializes and deserializes null, ignoring the actual values
+      // This is done for backward compatibility; troubleshooting-wise it might be better to throw
+      // exceptions
+      return new TypeAdapter<T>() {
+        @Override
+        public T read(JsonReader in) throws IOException {
+          in.skipValue();
+          return null;
+        }
+
+        @Override
+        public void write(JsonWriter out, T value) throws IOException {
+          out.nullValue();
+        }
+
+        @Override
+        public String toString() {
+          return "AnonymousOrNonStaticLocalClassAdapter";
+        }
+      };
+    }
+
     FilterResult filterResult =
         ReflectionAccessFilterHelper.getFilterResult(reflectionFilters, raw);
     if (filterResult == FilterResult.BLOCK_ALL) {
       throw new JsonIOException(
-          "ReflectionAccessFilter does not permit using reflection for " + raw
-          + ". Register a TypeAdapter for this type or adjust the access filter.");
+          "ReflectionAccessFilter does not permit using reflection for "
+              + raw
+              + ". Register a TypeAdapter for this type or adjust the access filter.");
     }
     boolean blockInaccessible = filterResult == FilterResult.BLOCK_INACCESSIBLE;
 
-    // If the type is actually a Java Record, we need to use the RecordAdapter instead. This will always be false
-    // on JVMs that do not support records.
+    // If the type is actually a Java Record, we need to use the RecordAdapter instead. This will
+    // always be false on JVMs that do not support records.
     if (ReflectionHelper.isRecord(raw)) {
       @SuppressWarnings("unchecked")
-      TypeAdapter<T> adapter = (TypeAdapter<T>) new RecordAdapter<>(raw,
-          getBoundFields(gson, type, raw, blockInaccessible, true), blockInaccessible);
+      TypeAdapter<T> adapter =
+          (TypeAdapter<T>)
+              new RecordAdapter<>(
+                  raw, getBoundFields(gson, type, raw, blockInaccessible, true), blockInaccessible);
       return adapter;
     }
 
     ObjectConstructor<T> constructor = constructorConstructor.get(type);
-    return new FieldReflectionAdapter<>(constructor, getBoundFields(gson, type, raw, blockInaccessible, false));
+    return new FieldReflectionAdapter<>(
+        constructor, getBoundFields(gson, type, raw, blockInaccessible, false));
   }
 
-  private static <M extends AccessibleObject & Member> void checkAccessible(Object object, M member) {
-    if (!ReflectionAccessFilterHelper.canAccess(member, Modifier.isStatic(member.getModifiers()) ? null : object)) {
+  private static <M extends AccessibleObject & Member> void checkAccessible(
+      Object object, M member) {
+    if (!ReflectionAccessFilterHelper.canAccess(
+        member, Modifier.isStatic(member.getModifiers()) ? null : object)) {
       String memberDescription = ReflectionHelper.getAccessibleObjectDescription(member, true);
-      throw new JsonIOException(memberDescription + " is not accessible and ReflectionAccessFilter does not"
-          + " permit making it accessible. Register a TypeAdapter for the declaring type, adjust the"
-          + " access filter or increase the visibility of the element and its declaring type.");
+      throw new JsonIOException(
+          memberDescription
+              + " is not accessible and ReflectionAccessFilter does not permit making it"
+              + " accessible. Register a TypeAdapter for the declaring type, adjust the access"
+              + " filter or increase the visibility of the element and its declaring type.");
     }
   }
 
   private BoundField createBoundField(
-      final Gson context, final Field field, final Method accessor, final String name,
-      final TypeToken<?> fieldType, boolean serialize, boolean deserialize,
+      final Gson context,
+      final Field field,
+      final Method accessor,
+      final String serializedName,
+      final TypeToken<?> fieldType,
+      final boolean serialize,
       final boolean blockInaccessible) {
 
     final boolean isPrimitive = Primitives.isPrimitive(fieldType.getRawType());
@@ -155,26 +192,30 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
     TypeAdapter<?> mapped = null;
     if (annotation != null) {
       // This is not safe; requires that user has specified correct adapter class for @JsonAdapter
-      mapped = jsonAdapterFactory.getTypeAdapter(
-          constructorConstructor, context, fieldType, annotation, false);
+      mapped =
+          jsonAdapterFactory.getTypeAdapter(
+              constructorConstructor, context, fieldType, annotation, false);
     }
     final boolean jsonAdapterPresent = mapped != null;
-    if (mapped == null) mapped = context.getAdapter(fieldType);
+    if (mapped == null) {
+      mapped = context.getAdapter(fieldType);
+    }
 
     @SuppressWarnings("unchecked")
     final TypeAdapter<Object> typeAdapter = (TypeAdapter<Object>) mapped;
     final TypeAdapter<Object> writeTypeAdapter;
     if (serialize) {
-      writeTypeAdapter = jsonAdapterPresent ? typeAdapter
-          : new TypeAdapterRuntimeTypeWrapper<>(context, typeAdapter, fieldType.getType());
+      writeTypeAdapter =
+          jsonAdapterPresent
+              ? typeAdapter
+              : new TypeAdapterRuntimeTypeWrapper<>(context, typeAdapter, fieldType.getType());
     } else {
       // Will never actually be used, but we set it to avoid confusing nullness-analysis tools
       writeTypeAdapter = typeAdapter;
     }
-    return new BoundField(name, field, serialize, deserialize) {
-      @Override void write(JsonWriter writer, Object source)
-          throws IOException, IllegalAccessException {
-        if (!serialized) return;
+    return new BoundField(serializedName, field) {
+      @Override
+      void write(JsonWriter writer, Object source) throws IOException, IllegalAccessException {
         if (blockInaccessible) {
           if (accessor == null) {
             checkAccessible(source, field);
@@ -190,8 +231,10 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
           try {
             fieldValue = accessor.invoke(source);
           } catch (InvocationTargetException e) {
-            String accessorDescription = ReflectionHelper.getAccessibleObjectDescription(accessor, false);
-            throw new JsonIOException("Accessor " + accessorDescription + " threw exception", e.getCause());
+            String accessorDescription =
+                ReflectionHelper.getAccessibleObjectDescription(accessor, false);
+            throw new JsonIOException(
+                "Accessor " + accessorDescription + " threw exception", e.getCause());
           }
         } else {
           fieldValue = field.get(source);
@@ -200,16 +243,20 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
           // avoid direct recursion
           return;
         }
-        writer.name(name);
+        writer.name(serializedName);
         writeTypeAdapter.write(writer, fieldValue);
       }
 
       @Override
-      void readIntoArray(JsonReader reader, int index, Object[] target) throws IOException, JsonParseException {
+      void readIntoArray(JsonReader reader, int index, Object[] target)
+          throws IOException, JsonParseException {
         Object fieldValue = typeAdapter.read(reader);
         if (fieldValue == null && isPrimitive) {
-          throw new JsonParseException("null is not allowed as value for record component '" + fieldName + "'"
-              + " of primitive type; at path " + reader.getPath());
+          throw new JsonParseException(
+              "null is not allowed as value for record component '"
+                  + fieldName
+                  + "' of primitive type; at path "
+                  + reader.getPath());
         }
         target[index] = fieldValue;
       }
@@ -222,7 +269,8 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
           if (blockInaccessible) {
             checkAccessible(target, field);
           } else if (isStaticFinalField) {
-            // Reflection does not permit setting value of `static final` field, even after calling `setAccessible`
+            // Reflection does not permit setting value of `static final` field, even after calling
+            // `setAccessible`
             // Handle this here to avoid causing IllegalAccessException when calling `Field.set`
             String fieldDescription = ReflectionHelper.getAccessibleObjectDescription(field, false);
             throw new JsonIOException("Cannot set value of 'static final' " + fieldDescription);
@@ -233,12 +281,48 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
     };
   }
 
-  private Map<String, BoundField> getBoundFields(Gson context, TypeToken<?> type, Class<?> raw,
-                                                 boolean blockInaccessible, boolean isRecord) {
-    Map<String, BoundField> result = new LinkedHashMap<>();
-    if (raw.isInterface()) {
-      return result;
+  private static class FieldsData {
+    public static final FieldsData EMPTY =
+        new FieldsData(
+            Collections.<String, BoundField>emptyMap(), Collections.<BoundField>emptyList());
+
+    /** Maps from JSON member name to field */
+    public final Map<String, BoundField> deserializedFields;
+
+    public final List<BoundField> serializedFields;
+
+    public FieldsData(
+        Map<String, BoundField> deserializedFields, List<BoundField> serializedFields) {
+      this.deserializedFields = deserializedFields;
+      this.serializedFields = serializedFields;
     }
+  }
+
+  private static IllegalArgumentException createDuplicateFieldException(
+      Class<?> declaringType, String duplicateName, Field field1, Field field2) {
+    throw new IllegalArgumentException(
+        "Class "
+            + declaringType.getName()
+            + " declares multiple JSON fields named '"
+            + duplicateName
+            + "'; conflict is caused by fields "
+            + ReflectionHelper.fieldToString(field1)
+            + " and "
+            + ReflectionHelper.fieldToString(field2)
+            + "\nSee "
+            + TroubleshootingGuide.createUrl("duplicate-fields"));
+  }
+
+  private FieldsData getBoundFields(
+      Gson context, TypeToken<?> type, Class<?> raw, boolean blockInaccessible, boolean isRecord) {
+    if (raw.isInterface()) {
+      return FieldsData.EMPTY;
+    }
+
+    Map<String, BoundField> deserializedFields = new LinkedHashMap<>();
+    // For serialized fields use a Map to track duplicate field names; otherwise this could be a
+    // List<BoundField> instead
+    Map<String, BoundField> serializedFields = new LinkedHashMap<>();
 
     Class<?> originalRaw = raw;
     while (raw != Object.class) {
@@ -246,11 +330,15 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
 
       // For inherited fields, check if access to their declaring class is allowed
       if (raw != originalRaw && fields.length > 0) {
-        FilterResult filterResult = ReflectionAccessFilterHelper.getFilterResult(reflectionFilters, raw);
+        FilterResult filterResult =
+            ReflectionAccessFilterHelper.getFilterResult(reflectionFilters, raw);
         if (filterResult == FilterResult.BLOCK_ALL) {
-          throw new JsonIOException("ReflectionAccessFilter does not permit using reflection for " + raw
-              + " (supertype of " + originalRaw + "). Register a TypeAdapter for this type"
-              + " or adjust the access filter.");
+          throw new JsonIOException(
+              "ReflectionAccessFilter does not permit using reflection for "
+                  + raw
+                  + " (supertype of "
+                  + originalRaw
+                  + "). Register a TypeAdapter for this type or adjust the access filter.");
         }
         blockInaccessible = filterResult == FilterResult.BLOCK_INACCESSIBLE;
       }
@@ -261,13 +349,16 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
         if (!serialize && !deserialize) {
           continue;
         }
-        // The accessor method is only used for records. If the type is a record, we will read out values
-        // via its accessor method instead of via reflection. This way we will bypass the accessible restrictions
+        // The accessor method is only used for records. If the type is a record, we will read out
+        // values via its accessor method instead of via reflection. This way we will bypass the
+        // accessible restrictions
         Method accessor = null;
         if (isRecord) {
-          // If there is a static field on a record, there will not be an accessor. Instead we will use the default
-          // field serialization logic, but for deserialization the field is excluded for simplicity. Note that Gson
-          // ignores static fields by default, but GsonBuilder.excludeFieldsWithModifiers can overwrite this.
+          // If there is a static field on a record, there will not be an accessor. Instead we will
+          // use the default field serialization logic, but for deserialization the field is
+          // excluded for simplicity.
+          // Note that Gson ignores static fields by default, but
+          // GsonBuilder.excludeFieldsWithModifiers can overwrite this.
           if (Modifier.isStatic(field.getModifiers())) {
             deserialize = false;
           } else {
@@ -278,12 +369,15 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
             }
 
             // @SerializedName can be placed on accessor method, but it is not supported there
-            // If field and method have annotation it is not easily possible to determine if accessor method
-            // is implicit and has inherited annotation, or if it is explicitly declared with custom annotation
+            // If field and method have annotation it is not easily possible to determine if
+            // accessor method is implicit and has inherited annotation, or if it is explicitly
+            // declared with custom annotation
             if (accessor.getAnnotation(SerializedName.class) != null
                 && field.getAnnotation(SerializedName.class) == null) {
-              String methodDescription = ReflectionHelper.getAccessibleObjectDescription(accessor, false);
-              throw new JsonIOException("@SerializedName on " + methodDescription + " is not supported");
+              String methodDescription =
+                  ReflectionHelper.getAccessibleObjectDescription(accessor, false);
+              throw new JsonIOException(
+                  "@SerializedName on " + methodDescription + " is not supported");
             }
           }
         }
@@ -293,54 +387,72 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
         if (!blockInaccessible && accessor == null) {
           ReflectionHelper.makeAccessible(field);
         }
+
         Type fieldType = $Gson$Types.resolve(type.getType(), raw, field.getGenericType());
         List<String> fieldNames = getFieldNames(field);
-        BoundField previous = null;
-        for (int i = 0, size = fieldNames.size(); i < size; ++i) {
-          String name = fieldNames.get(i);
-          if (i != 0) serialize = false; // only serialize the default name
-          BoundField boundField = createBoundField(context, field, accessor, name,
-              TypeToken.get(fieldType), serialize, deserialize, blockInaccessible);
-          BoundField replaced = result.put(name, boundField);
-          if (previous == null) previous = replaced;
+        String serializedName = fieldNames.get(0);
+        BoundField boundField =
+            createBoundField(
+                context,
+                field,
+                accessor,
+                serializedName,
+                TypeToken.get(fieldType),
+                serialize,
+                blockInaccessible);
+
+        if (deserialize) {
+          for (String name : fieldNames) {
+            BoundField replaced = deserializedFields.put(name, boundField);
+
+            if (replaced != null) {
+              throw createDuplicateFieldException(originalRaw, name, replaced.field, field);
+            }
+          }
         }
-        if (previous != null) {
-          throw new IllegalArgumentException("Class " + originalRaw.getName()
-              + " declares multiple JSON fields named '" + previous.name + "'; conflict is caused"
-              + " by fields " + ReflectionHelper.fieldToString(previous.field) + " and " + ReflectionHelper.fieldToString(field)
-              + "\nSee " + TroubleshootingGuide.createUrl("duplicate-fields"));
+
+        if (serialize) {
+          BoundField replaced = serializedFields.put(serializedName, boundField);
+          if (replaced != null) {
+            throw createDuplicateFieldException(originalRaw, serializedName, replaced.field, field);
+          }
         }
       }
       type = TypeToken.get($Gson$Types.resolve(type.getType(), raw, raw.getGenericSuperclass()));
       raw = type.getRawType();
     }
-    return result;
+    return new FieldsData(deserializedFields, new ArrayList<>(serializedFields.values()));
   }
 
-  static abstract class BoundField {
-    final String name;
+  abstract static class BoundField {
+    /** Name used for serialization (but not for deserialization) */
+    final String serializedName;
+
     final Field field;
+
     /** Name of the underlying field */
     final String fieldName;
-    final boolean serialized;
-    final boolean deserialized;
 
-    protected BoundField(String name, Field field, boolean serialized, boolean deserialized) {
-      this.name = name;
+    protected BoundField(String serializedName, Field field) {
+      this.serializedName = serializedName;
       this.field = field;
       this.fieldName = field.getName();
-      this.serialized = serialized;
-      this.deserialized = deserialized;
     }
 
     /** Read this field value from the source, and append its JSON value to the writer */
-    abstract void write(JsonWriter writer, Object source) throws IOException, IllegalAccessException;
+    abstract void write(JsonWriter writer, Object source)
+        throws IOException, IllegalAccessException;
 
     /** Read the value into the target array, used to provide constructor arguments for records */
-    abstract void readIntoArray(JsonReader reader, int index, Object[] target) throws IOException, JsonParseException;
+    abstract void readIntoArray(JsonReader reader, int index, Object[] target)
+        throws IOException, JsonParseException;
 
-    /** Read the value from the reader, and set it on the corresponding field on target via reflection */
-    abstract void readIntoField(JsonReader reader, Object target) throws IOException, IllegalAccessException;
+    /**
+     * Read the value from the reader, and set it on the corresponding field on target via
+     * reflection
+     */
+    abstract void readIntoField(JsonReader reader, Object target)
+        throws IOException, IllegalAccessException;
   }
 
   /**
@@ -349,19 +461,20 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
    * <p>The {@link RecordAdapter} is a special case to handle records for JVMs that support it, for
    * all other types we use the {@link FieldReflectionAdapter}. This class encapsulates the common
    * logic for serialization and deserialization. During deserialization, we construct an
-   * accumulator A, which we use to accumulate values from the source JSON. After the object has been read in
-   * full, the {@link #finalize(Object)} method is used to convert the accumulator to an instance
-   * of T.
+   * accumulator A, which we use to accumulate values from the source JSON. After the object has
+   * been read in full, the {@link #finalize(Object)} method is used to convert the accumulator to
+   * an instance of T.
    *
    * @param <T> type of objects that this Adapter creates.
    * @param <A> type of accumulator used to build the deserialization result.
    */
-  // This class is public because external projects check for this class with `instanceof` (even though it is internal)
-  public static abstract class Adapter<T, A> extends TypeAdapter<T> {
-    final Map<String, BoundField> boundFields;
+  // This class is public because external projects check for this class with `instanceof` (even
+  // though it is internal)
+  public abstract static class Adapter<T, A> extends TypeAdapter<T> {
+    private final FieldsData fieldsData;
 
-    Adapter(Map<String, BoundField> boundFields) {
-      this.boundFields = boundFields;
+    Adapter(FieldsData fieldsData) {
+      this.fieldsData = fieldsData;
     }
 
     @Override
@@ -373,7 +486,7 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
 
       out.beginObject();
       try {
-        for (BoundField boundField : boundFields.values()) {
+        for (BoundField boundField : fieldsData.serializedFields) {
           boundField.write(out, value);
         }
       } catch (IllegalAccessException e) {
@@ -390,13 +503,14 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
       }
 
       A accumulator = createAccumulator();
+      Map<String, BoundField> deserializedFields = fieldsData.deserializedFields;
 
       try {
         in.beginObject();
         while (in.hasNext()) {
           String name = in.nextName();
-          BoundField field = boundFields.get(name);
-          if (field == null || !field.deserialized) {
+          BoundField field = deserializedFields.get(name);
+          if (field == null) {
             in.skipValue();
           } else {
             readField(accumulator, in, field);
@@ -413,12 +527,14 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
 
     /** Create the Object that will be used to collect each field value */
     abstract A createAccumulator();
+
     /**
-     * Read a single BoundField into the accumulator. The JsonReader will be pointed at the
-     * start of the value for the BoundField to read from.
+     * Read a single BoundField into the accumulator. The JsonReader will be pointed at the start of
+     * the value for the BoundField to read from.
      */
     abstract void readField(A accumulator, JsonReader in, BoundField field)
         throws IllegalAccessException, IOException;
+
     /** Convert the accumulator to a final instance of T. */
     abstract T finalize(A accumulator);
   }
@@ -426,8 +542,8 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
   private static final class FieldReflectionAdapter<T> extends Adapter<T, T> {
     private final ObjectConstructor<T> constructor;
 
-    FieldReflectionAdapter(ObjectConstructor<T> constructor, Map<String, BoundField> boundFields) {
-      super(boundFields);
+    FieldReflectionAdapter(ObjectConstructor<T> constructor, FieldsData fieldsData) {
+      super(fieldsData);
       this.constructor = constructor;
     }
 
@@ -458,8 +574,8 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
     // Map from component names to index into the constructors arguments.
     private final Map<String, Integer> componentIndices = new HashMap<>();
 
-    RecordAdapter(Class<T> raw, Map<String, BoundField> boundFields, boolean blockInaccessible) {
-      super(boundFields);
+    RecordAdapter(Class<T> raw, FieldsData fieldsData, boolean blockInaccessible) {
+      super(fieldsData);
       constructor = ReflectionHelper.getCanonicalRecordConstructor(raw);
 
       if (blockInaccessible) {
@@ -475,8 +591,9 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
       }
       Class<?>[] parameterTypes = constructor.getParameterTypes();
 
-      // We need to ensure that we are passing non-null values to primitive fields in the constructor. To do this,
-      // we create an Object[] where all primitives are initialized to non-null values.
+      // We need to ensure that we are passing non-null values to primitive fields in the
+      // constructor. To do this, we create an Object[] where all primitives are initialized to
+      // non-null values.
       constructorArgsDefaults = new Object[parameterTypes.length];
       for (int i = 0; i < parameterTypes.length; i++) {
         // This will correctly be null for non-primitive types:
@@ -508,12 +625,15 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
       Integer componentIndex = componentIndices.get(field.fieldName);
       if (componentIndex == null) {
         throw new IllegalStateException(
-            "Could not find the index in the constructor '" + ReflectionHelper.constructorToString(constructor) + "'"
-                + " for field with name '" + field.fieldName + "',"
-                + " unable to determine which argument in the constructor the field corresponds"
+            "Could not find the index in the constructor '"
+                + ReflectionHelper.constructorToString(constructor)
+                + "' for field with name '"
+                + field.fieldName
+                + "', unable to determine which argument in the constructor the field corresponds"
                 + " to. This is unexpected behavior, as we expect the RecordComponents to have the"
                 + " same names as the fields in the Java class, and that the order of the"
-                + " RecordComponents is the same as the order of the canonical constructor parameters.");
+                + " RecordComponents is the same as the order of the canonical constructor"
+                + " parameters.");
       }
       field.readIntoArray(in, componentIndex, accumulator);
     }
@@ -526,17 +646,23 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
         throw ReflectionHelper.createExceptionForUnexpectedIllegalAccess(e);
       }
       // Note: InstantiationException should be impossible because record class is not abstract;
-      //  IllegalArgumentException should not be possible unless a bad adapter returns objects of the wrong type
+      //  IllegalArgumentException should not be possible unless a bad adapter returns objects of
+      //  the wrong type
       catch (InstantiationException | IllegalArgumentException e) {
         throw new RuntimeException(
-            "Failed to invoke constructor '" + ReflectionHelper.constructorToString(constructor) + "'"
-            + " with args " + Arrays.toString(accumulator), e);
-      }
-      catch (InvocationTargetException e) {
+            "Failed to invoke constructor '"
+                + ReflectionHelper.constructorToString(constructor)
+                + "' with args "
+                + Arrays.toString(accumulator),
+            e);
+      } catch (InvocationTargetException e) {
         // TODO: JsonParseException ?
         throw new RuntimeException(
-            "Failed to invoke constructor '" + ReflectionHelper.constructorToString(constructor) + "'"
-            + " with args " + Arrays.toString(accumulator), e.getCause());
+            "Failed to invoke constructor '"
+                + ReflectionHelper.constructorToString(constructor)
+                + "' with args "
+                + Arrays.toString(accumulator),
+            e.getCause());
       }
     }
   }

gson/src/main/java/com/google/gson/internal/bind/SerializationDelegatingTypeAdapter.java

@@ -18,13 +18,11 @@ package com.google.gson.internal.bind;
 
 import com.google.gson.TypeAdapter;
 
-/**
- * Type adapter which might delegate serialization to another adapter.
- */
+/** Type adapter which might delegate serialization to another adapter. */
 public abstract class SerializationDelegatingTypeAdapter<T> extends TypeAdapter<T> {
   /**
-   * Returns the adapter used for serialization, might be {@code this} or another adapter.
-   * That other adapter might itself also be a {@code SerializationDelegatingTypeAdapter}.
+   * Returns the adapter used for serialization, might be {@code this} or another adapter. That
+   * other adapter might itself also be a {@code SerializationDelegatingTypeAdapter}.
    */
   public abstract TypeAdapter<T> getSerializationDelegate();
 }

gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java

@@ -34,31 +34,38 @@ import java.io.IOException;
 import java.lang.reflect.Type;
 
 /**
- * Adapts a Gson 1.x tree-style adapter as a streaming TypeAdapter. Since the
- * tree adapter may be serialization-only or deserialization-only, this class
- * has a facility to lookup a delegate type adapter on demand.
+ * Adapts a Gson 1.x tree-style adapter as a streaming TypeAdapter. Since the tree adapter may be
+ * serialization-only or deserialization-only, this class has a facility to look up a delegate type
+ * adapter on demand.
  */
 public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter<T> {
   private final JsonSerializer<T> serializer;
   private final JsonDeserializer<T> deserializer;
   final Gson gson;
   private final TypeToken<T> typeToken;
+
   /**
-   * Only intended as {@code skipPast} for {@link Gson#getDelegateAdapter(TypeAdapterFactory, TypeToken)},
-   * must not be used in any other way.
+   * Only intended as {@code skipPast} for {@link Gson#getDelegateAdapter(TypeAdapterFactory,
+   * TypeToken)}, must not be used in any other way.
    */
   private final TypeAdapterFactory skipPastForGetDelegateAdapter;
+
   private final GsonContextImpl context = new GsonContextImpl();
   private final boolean nullSafe;
 
   /**
-   * The delegate is lazily created because it may not be needed, and creating it may fail.
-   * Field has to be {@code volatile} because {@link Gson} guarantees to be thread-safe.
+   * The delegate is lazily created because it may not be needed, and creating it may fail. Field
+   * has to be {@code volatile} because {@link Gson} guarantees to be thread-safe.
    */
   private volatile TypeAdapter<T> delegate;
 
-  public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deserializer,
-      Gson gson, TypeToken<T> typeToken, TypeAdapterFactory skipPast, boolean nullSafe) {
+  public TreeTypeAdapter(
+      JsonSerializer<T> serializer,
+      JsonDeserializer<T> deserializer,
+      Gson gson,
+      TypeToken<T> typeToken,
+      TypeAdapterFactory skipPast,
+      boolean nullSafe) {
     this.serializer = serializer;
     this.deserializer = deserializer;
     this.gson = gson;
@@ -67,12 +74,17 @@ public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter
     this.nullSafe = nullSafe;
   }
 
-  public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deserializer,
-                         Gson gson, TypeToken<T> typeToken, TypeAdapterFactory skipPast) {
+  public TreeTypeAdapter(
+      JsonSerializer<T> serializer,
+      JsonDeserializer<T> deserializer,
+      Gson gson,
+      TypeToken<T> typeToken,
+      TypeAdapterFactory skipPast) {
     this(serializer, deserializer, gson, typeToken, skipPast, true);
   }
 
-  @Override public T read(JsonReader in) throws IOException {
+  @Override
+  public T read(JsonReader in) throws IOException {
     if (deserializer == null) {
       return delegate().read(in);
     }
@@ -83,7 +95,8 @@ public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter
     return deserializer.deserialize(value, typeToken.getType(), context);
   }
 
-  @Override public void write(JsonWriter out, T value) throws IOException {
+  @Override
+  public void write(JsonWriter out, T value) throws IOException {
     if (serializer == null) {
       delegate().write(out, value);
       return;
@@ -97,7 +110,8 @@ public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter
   }
 
   private TypeAdapter<T> delegate() {
-    // A race might lead to `delegate` being assigned by multiple threads but the last assignment will stick
+    // A race might lead to `delegate` being assigned by multiple threads but the last assignment
+    // will stick
     TypeAdapter<T> d = delegate;
     return d != null
         ? d
@@ -105,25 +119,20 @@ public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter
   }
 
   /**
-   * Returns the type adapter which is used for serialization. Returns {@code this}
-   * if this {@code TreeTypeAdapter} has a {@link #serializer}; otherwise returns
-   * the delegate.
+   * Returns the type adapter which is used for serialization. Returns {@code this} if this {@code
+   * TreeTypeAdapter} has a {@link #serializer}; otherwise returns the delegate.
    */
-  @Override public TypeAdapter<T> getSerializationDelegate() {
+  @Override
+  public TypeAdapter<T> getSerializationDelegate() {
     return serializer != null ? this : delegate();
   }
 
-  /**
-   * Returns a new factory that will match each type against {@code exactType}.
-   */
+  /** Returns a new factory that will match each type against {@code exactType}. */
   public static TypeAdapterFactory newFactory(TypeToken<?> exactType, Object typeAdapter) {
     return new SingleTypeFactory(typeAdapter, exactType, false, null);
   }
 
-  /**
-   * Returns a new factory that will match each type and its raw type against
-   * {@code exactType}.
-   */
+  /** Returns a new factory that will match each type and its raw type against {@code exactType}. */
   public static TypeAdapterFactory newFactoryWithMatchRawType(
       TypeToken<?> exactType, Object typeAdapter) {
     // only bother matching raw types if exact type is a raw type
@@ -132,8 +141,8 @@ public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter
   }
 
   /**
-   * Returns a new factory that will match each type's raw type for assignability
-   * to {@code hierarchyType}.
+   * Returns a new factory that will match each type's raw type for assignability to {@code
+   * hierarchyType}.
    */
   public static TypeAdapterFactory newTypeHierarchyFactory(
       Class<?> hierarchyType, Object typeAdapter) {
@@ -147,14 +156,11 @@ public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter
     private final JsonSerializer<?> serializer;
     private final JsonDeserializer<?> deserializer;
 
-    SingleTypeFactory(Object typeAdapter, TypeToken<?> exactType, boolean matchRawType,
-        Class<?> hierarchyType) {
-      serializer = typeAdapter instanceof JsonSerializer
-          ? (JsonSerializer<?>) typeAdapter
-          : null;
-      deserializer = typeAdapter instanceof JsonDeserializer
-          ? (JsonDeserializer<?>) typeAdapter
-          : null;
+    SingleTypeFactory(
+        Object typeAdapter, TypeToken<?> exactType, boolean matchRawType, Class<?> hierarchyType) {
+      serializer = typeAdapter instanceof JsonSerializer ? (JsonSerializer<?>) typeAdapter : null;
+      deserializer =
+          typeAdapter instanceof JsonDeserializer ? (JsonDeserializer<?>) typeAdapter : null;
       $Gson$Preconditions.checkArgument(serializer != null || deserializer != null);
       this.exactType = exactType;
       this.matchRawType = matchRawType;
@@ -164,23 +170,29 @@ public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter
     @SuppressWarnings("unchecked") // guarded by typeToken.equals() call
     @Override
     public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
-      boolean matches = exactType != null
-          ? exactType.equals(type) || (matchRawType && exactType.getType() == type.getRawType())
-          : hierarchyType.isAssignableFrom(type.getRawType());
+      boolean matches =
+          exactType != null
+              ? exactType.equals(type) || (matchRawType && exactType.getType() == type.getRawType())
+              : hierarchyType.isAssignableFrom(type.getRawType());
       return matches
-          ? new TreeTypeAdapter<>((JsonSerializer<T>) serializer,
-              (JsonDeserializer<T>) deserializer, gson, type, this)
+          ? new TreeTypeAdapter<>(
+              (JsonSerializer<T>) serializer, (JsonDeserializer<T>) deserializer, gson, type, this)
           : null;
     }
   }
 
-  private final class GsonContextImpl implements JsonSerializationContext, JsonDeserializationContext {
-    @Override public JsonElement serialize(Object src) {
+  private final class GsonContextImpl
+      implements JsonSerializationContext, JsonDeserializationContext {
+    @Override
+    public JsonElement serialize(Object src) {
       return gson.toJsonTree(src);
     }
-    @Override public JsonElement serialize(Object src, Type typeOfSrc) {
+
+    @Override
+    public JsonElement serialize(Object src, Type typeOfSrc) {
       return gson.toJsonTree(src, typeOfSrc);
     }
+
     @Override
     @SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
     public <R> R deserialize(JsonElement json, Type typeOfT) throws JsonParseException {

gson/src/main/java/com/google/gson/internal/bind/TypeAdapterRuntimeTypeWrapper.java

@@ -1,101 +1,103 @@
-/*
- * Copyright (C) 2011 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.google.gson.internal.bind;
-
-import com.google.gson.Gson;
-import com.google.gson.TypeAdapter;
-import com.google.gson.reflect.TypeToken;
-import com.google.gson.stream.JsonReader;
-import com.google.gson.stream.JsonWriter;
-import java.io.IOException;
-import java.lang.reflect.Type;
-import java.lang.reflect.TypeVariable;
-
-final class TypeAdapterRuntimeTypeWrapper<T> extends TypeAdapter<T> {
-  private final Gson context;
-  private final TypeAdapter<T> delegate;
-  private final Type type;
-
-  TypeAdapterRuntimeTypeWrapper(Gson context, TypeAdapter<T> delegate, Type type) {
-    this.context = context;
-    this.delegate = delegate;
-    this.type = type;
-  }
-
-  @Override
-  public T read(JsonReader in) throws IOException {
-    return delegate.read(in);
-  }
-
-  @Override
-  public void write(JsonWriter out, T value) throws IOException {
-    // Order of preference for choosing type adapters
-    // First preference: a type adapter registered for the runtime type
-    // Second preference: a type adapter registered for the declared type
-    // Third preference: reflective type adapter for the runtime type (if it is a sub class of the declared type)
-    // Fourth preference: reflective type adapter for the declared type
-
-    TypeAdapter<T> chosen = delegate;
-    Type runtimeType = getRuntimeTypeIfMoreSpecific(type, value);
-    if (runtimeType != type) {
-      @SuppressWarnings("unchecked")
-      TypeAdapter<T> runtimeTypeAdapter = (TypeAdapter<T>) context.getAdapter(TypeToken.get(runtimeType));
-      // For backward compatibility only check ReflectiveTypeAdapterFactory.Adapter here but not any other
-      // wrapping adapters, see https://github.com/google/gson/pull/1787#issuecomment-1222175189
-      if (!(runtimeTypeAdapter instanceof ReflectiveTypeAdapterFactory.Adapter)) {
-        // The user registered a type adapter for the runtime type, so we will use that
-        chosen = runtimeTypeAdapter;
-      } else if (!isReflective(delegate)) {
-        // The user registered a type adapter for Base class, so we prefer it over the
-        // reflective type adapter for the runtime type
-        chosen = delegate;
-      } else {
-        // Use the type adapter for runtime type
-        chosen = runtimeTypeAdapter;
-      }
-    }
-    chosen.write(out, value);
-  }
-
-  /**
-   * Returns whether the type adapter uses reflection.
-   *
-   * @param typeAdapter the type adapter to check.
-   */
-  private static boolean isReflective(TypeAdapter<?> typeAdapter) {
-    // Run this in loop in case multiple delegating adapters are nested
-    while (typeAdapter instanceof SerializationDelegatingTypeAdapter) {
-      TypeAdapter<?> delegate = ((SerializationDelegatingTypeAdapter<?>) typeAdapter).getSerializationDelegate();
-      // Break if adapter does not delegate serialization
-      if (delegate == typeAdapter) {
-        break;
-      }
-      typeAdapter = delegate;
-    }
-
-    return typeAdapter instanceof ReflectiveTypeAdapterFactory.Adapter;
-  }
-
-  /**
-   * Finds a compatible runtime type if it is more specific
-   */
-  private static Type getRuntimeTypeIfMoreSpecific(Type type, Object value) {
-    if (value != null && (type instanceof Class<?> || type instanceof TypeVariable<?>)) {
-      type = value.getClass();
-    }
-    return type;
-  }
-}
+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.gson.internal.bind;
+
+import com.google.gson.Gson;
+import com.google.gson.TypeAdapter;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.lang.reflect.TypeVariable;
+
+final class TypeAdapterRuntimeTypeWrapper<T> extends TypeAdapter<T> {
+  private final Gson context;
+  private final TypeAdapter<T> delegate;
+  private final Type type;
+
+  TypeAdapterRuntimeTypeWrapper(Gson context, TypeAdapter<T> delegate, Type type) {
+    this.context = context;
+    this.delegate = delegate;
+    this.type = type;
+  }
+
+  @Override
+  public T read(JsonReader in) throws IOException {
+    return delegate.read(in);
+  }
+
+  @Override
+  public void write(JsonWriter out, T value) throws IOException {
+    // Order of preference for choosing type adapters
+    // First preference: a type adapter registered for the runtime type
+    // Second preference: a type adapter registered for the declared type
+    // Third preference: reflective type adapter for the runtime type
+    //                   (if it is a subclass of the declared type)
+    // Fourth preference: reflective type adapter for the declared type
+
+    TypeAdapter<T> chosen = delegate;
+    Type runtimeType = getRuntimeTypeIfMoreSpecific(type, value);
+    if (runtimeType != type) {
+      @SuppressWarnings("unchecked")
+      TypeAdapter<T> runtimeTypeAdapter =
+          (TypeAdapter<T>) context.getAdapter(TypeToken.get(runtimeType));
+      // For backward compatibility only check ReflectiveTypeAdapterFactory.Adapter here but not any
+      // other wrapping adapters, see
+      // https://github.com/google/gson/pull/1787#issuecomment-1222175189
+      if (!(runtimeTypeAdapter instanceof ReflectiveTypeAdapterFactory.Adapter)) {
+        // The user registered a type adapter for the runtime type, so we will use that
+        chosen = runtimeTypeAdapter;
+      } else if (!isReflective(delegate)) {
+        // The user registered a type adapter for Base class, so we prefer it over the
+        // reflective type adapter for the runtime type
+        chosen = delegate;
+      } else {
+        // Use the type adapter for runtime type
+        chosen = runtimeTypeAdapter;
+      }
+    }
+    chosen.write(out, value);
+  }
+
+  /**
+   * Returns whether the type adapter uses reflection.
+   *
+   * @param typeAdapter the type adapter to check.
+   */
+  private static boolean isReflective(TypeAdapter<?> typeAdapter) {
+    // Run this in loop in case multiple delegating adapters are nested
+    while (typeAdapter instanceof SerializationDelegatingTypeAdapter) {
+      TypeAdapter<?> delegate =
+          ((SerializationDelegatingTypeAdapter<?>) typeAdapter).getSerializationDelegate();
+      // Break if adapter does not delegate serialization
+      if (delegate == typeAdapter) {
+        break;
+      }
+      typeAdapter = delegate;
+    }
+
+    return typeAdapter instanceof ReflectiveTypeAdapterFactory.Adapter;
+  }
+
+  /** Finds a compatible runtime type if it is more specific */
+  private static Type getRuntimeTypeIfMoreSpecific(Type type, Object value) {
+    if (value != null && (type instanceof Class<?> || type instanceof TypeVariable<?>)) {
+      type = value.getClass();
+    }
+    return type;
+  }
+}

gson/src/main/java/com/google/gson/internal/package-info.java

@@ -15,8 +15,8 @@
  */
 
 /**
- * Do NOT use any class in this package as they are meant for internal use in Gson.
- * These classes will very likely change incompatibly in future versions. You have been warned.
+ * Do NOT use any class in this package as they are meant for internal use in Gson. These classes
+ * will very likely change incompatibly in future versions. You have been warned.
  *
  * @author Inderjeet Singh, Joel Leitch, Jesse Wilson
  */

gson/src/main/java/com/google/gson/internal/reflect/ReflectionHelper.java

@@ -23,6 +23,7 @@ import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
 
 public class ReflectionHelper {
 
@@ -31,7 +32,8 @@ public class ReflectionHelper {
   static {
     RecordHelper instance;
     try {
-      // Try to construct the RecordSupportedHelper, if this fails, records are not supported on this JVM.
+      // Try to construct the RecordSupportedHelper, if this fails, records are not supported on
+      // this JVM.
       instance = new RecordSupportedHelper();
     } catch (ReflectiveOperationException e) {
       instance = new RecordNotSupportedHelper();
@@ -45,8 +47,10 @@ public class ReflectionHelper {
     // Class was added in Java 9, therefore cannot use instanceof
     if (e.getClass().getName().equals("java.lang.reflect.InaccessibleObjectException")) {
       String message = e.getMessage();
-      String troubleshootingId = message != null && message.contains("to module com.google.gson")
-          ? "reflection-inaccessible-to-module-gson" : "reflection-inaccessible";
+      String troubleshootingId =
+          message != null && message.contains("to module com.google.gson")
+              ? "reflection-inaccessible-to-module-gson"
+              : "reflection-inaccessible";
       return "\nSee " + TroubleshootingGuide.createUrl(troubleshootingId);
     }
     return "";
@@ -55,7 +59,8 @@ public class ReflectionHelper {
   /**
    * Internal implementation of making an {@link AccessibleObject} accessible.
    *
-   * @param object the object that {@link AccessibleObject#setAccessible(boolean)} should be called on.
+   * @param object the object that {@link AccessibleObject#setAccessible(boolean)} should be called
+   *     on.
    * @throws JsonIOException if making the object accessible fails
    */
   public static void makeAccessible(AccessibleObject object) throws JsonIOException {
@@ -63,22 +68,26 @@ public class ReflectionHelper {
       object.setAccessible(true);
     } catch (Exception exception) {
       String description = getAccessibleObjectDescription(object, false);
-      throw new JsonIOException("Failed making " + description + " accessible; either increase its visibility"
-          + " or write a custom TypeAdapter for its declaring type." + getInaccessibleTroubleshootingSuffix(exception),
+      throw new JsonIOException(
+          "Failed making "
+              + description
+              + " accessible; either increase its visibility"
+              + " or write a custom TypeAdapter for its declaring type."
+              + getInaccessibleTroubleshootingSuffix(exception),
           exception);
     }
   }
 
   /**
-   * Returns a short string describing the {@link AccessibleObject} in a human-readable way.
-   * The result is normally shorter than {@link AccessibleObject#toString()} because it omits
-   * modifiers (e.g. {@code final}) and uses simple names for constructor and method parameter
-   * types.
+   * Returns a short string describing the {@link AccessibleObject} in a human-readable way. The
+   * result is normally shorter than {@link AccessibleObject#toString()} because it omits modifiers
+   * (e.g. {@code final}) and uses simple names for constructor and method parameter types.
    *
    * @param object object to describe
    * @param uppercaseFirstLetter whether the first letter of the description should be uppercased
    */
-  public static String getAccessibleObjectDescription(AccessibleObject object, boolean uppercaseFirstLetter) {
+  public static String getAccessibleObjectDescription(
+      AccessibleObject object, boolean uppercaseFirstLetter) {
     String description;
 
     if (object instanceof Field) {
@@ -103,17 +112,14 @@ public class ReflectionHelper {
     return description;
   }
 
-  /**
-   * Creates a string representation for a field, omitting modifiers and
-   * the field type.
-   */
+  /** Creates a string representation for a field, omitting modifiers and the field type. */
   public static String fieldToString(Field field) {
     return field.getDeclaringClass().getName() + "#" + field.getName();
   }
 
   /**
-   * Creates a string representation for a constructor.
-   * E.g.: {@code java.lang.String(char[], int, int)}
+   * Creates a string representation for a constructor. E.g.: {@code java.lang.String(char[], int,
+   * int)}
    */
   public static String constructorToString(Constructor<?> constructor) {
     StringBuilder stringBuilder = new StringBuilder(constructor.getDeclaringClass().getName());
@@ -122,13 +128,15 @@ public class ReflectionHelper {
     return stringBuilder.toString();
   }
 
-  // Note: Ideally parameter type would be java.lang.reflect.Executable, but that was added in Java 8
-  private static void appendExecutableParameters(AccessibleObject executable, StringBuilder stringBuilder) {
+  // Ideally parameter type would be java.lang.reflect.Executable, but that was added in Java 8
+  private static void appendExecutableParameters(
+      AccessibleObject executable, StringBuilder stringBuilder) {
     stringBuilder.append('(');
 
-    Class<?>[] parameters = (executable instanceof Method)
-        ? ((Method) executable).getParameterTypes()
-        : ((Constructor<?>) executable).getParameterTypes();
+    Class<?>[] parameters =
+        (executable instanceof Method)
+            ? ((Method) executable).getParameterTypes()
+            : ((Constructor<?>) executable).getParameterTypes();
     for (int i = 0; i < parameters.length; i++) {
       if (i > 0) {
         stringBuilder.append(", ");
@@ -139,23 +147,33 @@ public class ReflectionHelper {
     stringBuilder.append(')');
   }
 
+  public static boolean isStatic(Class<?> clazz) {
+    return Modifier.isStatic(clazz.getModifiers());
+  }
+
+  /** Returns whether the class is anonymous or a non-static local class. */
+  public static boolean isAnonymousOrNonStaticLocal(Class<?> clazz) {
+    return !isStatic(clazz) && (clazz.isAnonymousClass() || clazz.isLocalClass());
+  }
+
   /**
-   * Tries making the constructor accessible, returning an exception message
-   * if this fails.
+   * Tries making the constructor accessible, returning an exception message if this fails.
    *
    * @param constructor constructor to make accessible
-   * @return exception message; {@code null} if successful, non-{@code null} if
-   *    unsuccessful
+   * @return exception message; {@code null} if successful, non-{@code null} if unsuccessful
    */
   public static String tryMakeAccessible(Constructor<?> constructor) {
     try {
       constructor.setAccessible(true);
       return null;
     } catch (Exception exception) {
-      return "Failed making constructor '" + constructorToString(constructor) + "' accessible;"
-          + " either increase its visibility or write a custom InstanceCreator or TypeAdapter for"
+      return "Failed making constructor '"
+          + constructorToString(constructor)
+          + "' accessible; either increase its visibility or write a custom InstanceCreator or"
+          + " TypeAdapter for its declaring type: "
           // Include the message since it might contain more detailed information
-          + " its declaring type: " + exception.getMessage() + getInaccessibleTroubleshootingSuffix(exception);
+          + exception.getMessage()
+          + getInaccessibleTroubleshootingSuffix(exception);
     }
   }
 
@@ -179,26 +197,28 @@ public class ReflectionHelper {
 
   public static RuntimeException createExceptionForUnexpectedIllegalAccess(
       IllegalAccessException exception) {
-    throw new RuntimeException("Unexpected IllegalAccessException occurred (Gson " + GsonBuildConfig.VERSION + ")."
-        + " Certain ReflectionAccessFilter features require Java >= 9 to work correctly. If you are not using"
-        + " ReflectionAccessFilter, report this to the Gson maintainers.",
+    throw new RuntimeException(
+        "Unexpected IllegalAccessException occurred (Gson "
+            + GsonBuildConfig.VERSION
+            + "). Certain ReflectionAccessFilter features require Java >= 9 to work correctly. If"
+            + " you are not using ReflectionAccessFilter, report this to the Gson maintainers.",
         exception);
   }
 
-
   private static RuntimeException createExceptionForRecordReflectionException(
-          ReflectiveOperationException exception) {
-    throw new RuntimeException("Unexpected ReflectiveOperationException occurred"
-            + " (Gson " + GsonBuildConfig.VERSION + ")."
+      ReflectiveOperationException exception) {
+    throw new RuntimeException(
+        "Unexpected ReflectiveOperationException occurred"
+            + " (Gson "
+            + GsonBuildConfig.VERSION
+            + ")."
             + " To support Java records, reflection is utilized to read out information"
             + " about records. All these invocations happens after it is established"
             + " that records exist in the JVM. This exception is unexpected behavior.",
-            exception);
+        exception);
   }
 
-  /**
-   * Internal abstraction over reflection when Records are supported.
-   */
+  /** Internal abstraction over reflection when Records are supported. */
   private abstract static class RecordHelper {
     abstract boolean isRecord(Class<?> clazz);
 
@@ -254,8 +274,8 @@ public class ReflectionHelper {
         for (int i = 0; i < recordComponents.length; i++) {
           recordComponentTypes[i] = (Class<?>) getType.invoke(recordComponents[i]);
         }
-        // Uses getDeclaredConstructor because implicit constructor has same visibility as record and might
-        // therefore not be public
+        // Uses getDeclaredConstructor because implicit constructor has same visibility as record
+        // and might therefore not be public
         return raw.getDeclaredConstructor(recordComponentTypes);
       } catch (ReflectiveOperationException e) {
         throw createExceptionForRecordReflectionException(e);
@@ -265,8 +285,9 @@ public class ReflectionHelper {
     @Override
     public Method getAccessor(Class<?> raw, Field field) {
       try {
-        // Records consists of record components, each with a unique name, a corresponding field and accessor method
-        // with the same name. Ref.: https://docs.oracle.com/javase/specs/jls/se17/html/jls-8.html#jls-8.10.3
+        // Records consists of record components, each with a unique name, a corresponding field and
+        // accessor method with the same name. Ref.:
+        // https://docs.oracle.com/javase/specs/jls/se17/html/jls-8.html#jls-8.10.3
         return raw.getMethod(field.getName());
       } catch (ReflectiveOperationException e) {
         throw createExceptionForRecordReflectionException(e);
@@ -274,9 +295,7 @@ public class ReflectionHelper {
     }
   }
 
-  /**
-   * Instance used when records are not supported
-   */
+  /** Instance used when records are not supported */
   private static class RecordNotSupportedHelper extends RecordHelper {
 
     @Override
@@ -287,19 +306,19 @@ public class ReflectionHelper {
     @Override
     String[] getRecordComponentNames(Class<?> clazz) {
       throw new UnsupportedOperationException(
-              "Records are not supported on this JVM, this method should not be called");
+          "Records are not supported on this JVM, this method should not be called");
     }
 
     @Override
     <T> Constructor<T> getCanonicalRecordConstructor(Class<T> raw) {
       throw new UnsupportedOperationException(
-              "Records are not supported on this JVM, this method should not be called");
+          "Records are not supported on this JVM, this method should not be called");
     }
 
     @Override
     public Method getAccessor(Class<?> raw, Field field) {
       throw new UnsupportedOperationException(
-              "Records are not supported on this JVM, this method should not be called");
+          "Records are not supported on this JVM, this method should not be called");
     }
   }
 }

gson/src/main/java/com/google/gson/internal/sql/SqlDateTypeAdapter.java

@@ -29,27 +29,29 @@ import java.text.DateFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
+import java.util.TimeZone;
 
 /**
- * Adapter for java.sql.Date. Although this class appears stateless, it is not.
- * DateFormat captures its time zone and locale when it is created, which gives
- * this class state. DateFormat isn't thread safe either, so this class has
- * to synchronize its read and write methods.
+ * Adapter for java.sql.Date. Although this class appears stateless, it is not. DateFormat captures
+ * its time zone and locale when it is created, which gives this class state. DateFormat isn't
+ * thread safe either, so this class has to synchronize its read and write methods.
  */
 @SuppressWarnings("JavaUtilDate")
 final class SqlDateTypeAdapter extends TypeAdapter<java.sql.Date> {
-  static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
-    @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
-    @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
-      return typeToken.getRawType() == java.sql.Date.class
-          ? (TypeAdapter<T>) new SqlDateTypeAdapter() : null;
-    }
-  };
+  static final TypeAdapterFactory FACTORY =
+      new TypeAdapterFactory() {
+        @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
+        @Override
+        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+          return typeToken.getRawType() == java.sql.Date.class
+              ? (TypeAdapter<T>) new SqlDateTypeAdapter()
+              : null;
+        }
+      };
 
   private final DateFormat format = new SimpleDateFormat("MMM d, yyyy");
 
-  private SqlDateTypeAdapter() {
-  }
+  private SqlDateTypeAdapter() {}
 
   @Override
   public java.sql.Date read(JsonReader in) throws IOException {
@@ -58,14 +60,17 @@ final class SqlDateTypeAdapter extends TypeAdapter<java.sql.Date> {
       return null;
     }
     String s = in.nextString();
-    try {
-      Date utilDate;
-      synchronized (this) {
-        utilDate = format.parse(s);
+    synchronized (this) {
+      TimeZone originalTimeZone = format.getTimeZone(); // Save the original time zone
+      try {
+        Date utilDate = format.parse(s);
+        return new java.sql.Date(utilDate.getTime());
+      } catch (ParseException e) {
+        throw new JsonSyntaxException(
+            "Failed parsing '" + s + "' as SQL Date; at path " + in.getPreviousPath(), e);
+      } finally {
+        format.setTimeZone(originalTimeZone); // Restore the original time zone after parsing
       }
-      return new java.sql.Date(utilDate.getTime());
-    } catch (ParseException e) {
-      throw new JsonSyntaxException("Failed parsing '" + s + "' as SQL Date; at path " + in.getPreviousPath(), e);
     }
   }
 

gson/src/main/java/com/google/gson/internal/sql/SqlTimeTypeAdapter.java

@@ -30,44 +30,53 @@ import java.text.DateFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
+import java.util.TimeZone;
 
 /**
- * Adapter for java.sql.Time. Although this class appears stateless, it is not.
- * DateFormat captures its time zone and locale when it is created, which gives
- * this class state. DateFormat isn't thread safe either, so this class has
- * to synchronize its read and write methods.
+ * Adapter for java.sql.Time. Although this class appears stateless, it is not. DateFormat captures
+ * its time zone and locale when it is created, which gives this class state. DateFormat isn't
+ * thread safe either, so this class has to synchronize its read and write methods.
  */
 @SuppressWarnings("JavaUtilDate")
 final class SqlTimeTypeAdapter extends TypeAdapter<Time> {
-  static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
-    @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
-    @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
-      return typeToken.getRawType() == Time.class ? (TypeAdapter<T>) new SqlTimeTypeAdapter() : null;
-    }
-  };
+  static final TypeAdapterFactory FACTORY =
+      new TypeAdapterFactory() {
+        @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
+        @Override
+        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+          return typeToken.getRawType() == Time.class
+              ? (TypeAdapter<T>) new SqlTimeTypeAdapter()
+              : null;
+        }
+      };
 
   private final DateFormat format = new SimpleDateFormat("hh:mm:ss a");
 
-  private SqlTimeTypeAdapter() {
-  }
+  private SqlTimeTypeAdapter() {}
 
-  @Override public Time read(JsonReader in) throws IOException {
+  @Override
+  public Time read(JsonReader in) throws IOException {
     if (in.peek() == JsonToken.NULL) {
       in.nextNull();
       return null;
     }
     String s = in.nextString();
-    try {
-      synchronized (this) {
+    synchronized (this) {
+      TimeZone originalTimeZone = format.getTimeZone(); // Save the original time zone
+      try {
         Date date = format.parse(s);
         return new Time(date.getTime());
+      } catch (ParseException e) {
+        throw new JsonSyntaxException(
+            "Failed parsing '" + s + "' as SQL Time; at path " + in.getPreviousPath(), e);
+      } finally {
+        format.setTimeZone(originalTimeZone); // Restore the original time zone
       }
-    } catch (ParseException e) {
-      throw new JsonSyntaxException("Failed parsing '" + s + "' as SQL Time; at path " + in.getPreviousPath(), e);
     }
   }
 
-  @Override public void write(JsonWriter out, Time value) throws IOException {
+  @Override
+  public void write(JsonWriter out, Time value) throws IOException {
     if (value == null) {
       out.nullValue();
       return;

gson/src/main/java/com/google/gson/internal/sql/SqlTimestampTypeAdapter.java

@@ -22,24 +22,25 @@ import com.google.gson.TypeAdapterFactory;
 import com.google.gson.reflect.TypeToken;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
-
 import java.io.IOException;
 import java.sql.Timestamp;
 import java.util.Date;
 
 @SuppressWarnings("JavaUtilDate")
 class SqlTimestampTypeAdapter extends TypeAdapter<Timestamp> {
-  static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
-    @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
-    @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
-      if (typeToken.getRawType() == Timestamp.class) {
-        final TypeAdapter<Date> dateTypeAdapter = gson.getAdapter(Date.class);
-        return (TypeAdapter<T>) new SqlTimestampTypeAdapter(dateTypeAdapter);
-      } else {
-        return null;
-      }
-    }
-  };
+  static final TypeAdapterFactory FACTORY =
+      new TypeAdapterFactory() {
+        @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
+        @Override
+        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+          if (typeToken.getRawType() == Timestamp.class) {
+            final TypeAdapter<Date> dateTypeAdapter = gson.getAdapter(Date.class);
+            return (TypeAdapter<T>) new SqlTimestampTypeAdapter(dateTypeAdapter);
+          } else {
+            return null;
+          }
+        }
+      };
 
   private final TypeAdapter<Date> dateTypeAdapter;
 

gson/src/main/java/com/google/gson/internal/sql/SqlTypesSupport.java

@@ -16,29 +16,23 @@
 
 package com.google.gson.internal.sql;
 
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.internal.bind.DefaultDateTypeAdapter.DateType;
 import java.sql.Timestamp;
 import java.util.Date;
 
-import com.google.gson.TypeAdapterFactory;
-import com.google.gson.internal.bind.DefaultDateTypeAdapter.DateType;
-
 /**
- * Encapsulates access to {@code java.sql} types, to allow Gson to
- * work without the {@code java.sql} module being present.
- * No {@link ClassNotFoundException}s will be thrown in case
- * the {@code java.sql} module is not present.
+ * Encapsulates access to {@code java.sql} types, to allow Gson to work without the {@code java.sql}
+ * module being present. No {@link ClassNotFoundException}s will be thrown in case the {@code
+ * java.sql} module is not present.
  *
- * <p>If {@link #SUPPORTS_SQL_TYPES} is {@code true}, all other
- * constants of this class will be non-{@code null}. However, if
- * it is {@code false} all other constants will be {@code null} and
+ * <p>If {@link #SUPPORTS_SQL_TYPES} is {@code true}, all other constants of this class will be
+ * non-{@code null}. However, if it is {@code false} all other constants will be {@code null} and
  * there will be no support for {@code java.sql} types.
  */
 @SuppressWarnings("JavaUtilDate")
 public final class SqlTypesSupport {
-  /**
-   * {@code true} if {@code java.sql} types are supported,
-   * {@code false} otherwise
-   */
+  /** {@code true} if {@code java.sql} types are supported, {@code false} otherwise */
   public static final boolean SUPPORTS_SQL_TYPES;
 
   public static final DateType<? extends Date> DATE_DATE_TYPE;
@@ -59,16 +53,20 @@ public final class SqlTypesSupport {
     SUPPORTS_SQL_TYPES = sqlTypesSupport;
 
     if (SUPPORTS_SQL_TYPES) {
-      DATE_DATE_TYPE = new DateType<java.sql.Date>(java.sql.Date.class) {
-        @Override protected java.sql.Date deserialize(Date date) {
-          return new java.sql.Date(date.getTime());
-        }
-      };
-      TIMESTAMP_DATE_TYPE = new DateType<Timestamp>(Timestamp.class) {
-        @Override protected Timestamp deserialize(Date date) {
-          return new Timestamp(date.getTime());
-        }
-      };
+      DATE_DATE_TYPE =
+          new DateType<java.sql.Date>(java.sql.Date.class) {
+            @Override
+            protected java.sql.Date deserialize(Date date) {
+              return new java.sql.Date(date.getTime());
+            }
+          };
+      TIMESTAMP_DATE_TYPE =
+          new DateType<Timestamp>(Timestamp.class) {
+            @Override
+            protected Timestamp deserialize(Date date) {
+              return new Timestamp(date.getTime());
+            }
+          };
 
       DATE_FACTORY = SqlDateTypeAdapter.FACTORY;
       TIME_FACTORY = SqlTimeTypeAdapter.FACTORY;
@@ -83,6 +81,5 @@ public final class SqlTypesSupport {
     }
   }
 
-  private SqlTypesSupport() {
-  }
+  private SqlTypesSupport() {}
 }

gson/src/main/java/com/google/gson/package-info.java

@@ -18,9 +18,9 @@
  * This package provides the {@link com.google.gson.Gson} class to convert Json to Java and
  * vice-versa.
  *
- * <p>The primary class to use is {@link com.google.gson.Gson} which can be constructed with
- * {@code new Gson()} (using default settings) or by using {@link com.google.gson.GsonBuilder}
- * (to configure various options such as using versioning and so on).</p>
+ * <p>The primary class to use is {@link com.google.gson.Gson} which can be constructed with {@code
+ * new Gson()} (using default settings) or by using {@link com.google.gson.GsonBuilder} (to
+ * configure various options such as using versioning and so on).
  *
  * @author Inderjeet Singh, Joel Leitch
  */

gson/src/main/java/com/google/gson/reflect/TypeToken.java

@@ -28,28 +28,24 @@ import java.util.Map;
 import java.util.Objects;
 
 /**
- * Represents a generic type {@code T}. Java doesn't yet provide a way to
- * represent generic types, so this class does. Forces clients to create a
- * subclass of this class which enables retrieval the type information even at
- * runtime.
+ * Represents a generic type {@code T}. Java doesn't yet provide a way to represent generic types,
+ * so this class does. Forces clients to create a subclass of this class which enables retrieval the
+ * type information even at runtime.
  *
- * <p>For example, to create a type literal for {@code List<String>}, you can
- * create an empty anonymous class:
+ * <p>For example, to create a type literal for {@code List<String>}, you can create an empty
+ * anonymous class:
  *
- * <p>
- * {@code TypeToken<List<String>> list = new TypeToken<List<String>>() {};}
+ * <p>{@code TypeToken<List<String>> list = new TypeToken<List<String>>() {};}
  *
- * <p>Capturing a type variable as type argument of an anonymous {@code TypeToken}
- * subclass is not allowed, for example {@code TypeToken<List<T>>}.
- * Due to type erasure the runtime type of a type variable is not available
- * to Gson and therefore it cannot provide the functionality one might expect.
- * This would give a false sense of type-safety at compile time and could
- * lead to an unexpected {@code ClassCastException} at runtime.
+ * <p>Capturing a type variable as type argument of an anonymous {@code TypeToken} subclass is not
+ * allowed, for example {@code TypeToken<List<T>>}. Due to type erasure the runtime type of a type
+ * variable is not available to Gson and therefore it cannot provide the functionality one might
+ * expect. This would give a false sense of type-safety at compile time and could lead to an
+ * unexpected {@code ClassCastException} at runtime.
  *
- * <p>If the type arguments of the parameterized type are only available at
- * runtime, for example when you want to create a {@code List<E>} based on
- * a {@code Class<E>} representing the element type, the method
- * {@link #getParameterized(Type, Type...)} can be used.
+ * <p>If the type arguments of the parameterized type are only available at runtime, for example
+ * when you want to create a {@code List<E>} based on a {@code Class<E>} representing the element
+ * type, the method {@link #getParameterized(Type, Type...)} can be used.
  *
  * @author Bob Lee
  * @author Sven Mawson
@@ -61,19 +57,17 @@ public class TypeToken<T> {
   private final int hashCode;
 
   /**
-   * Constructs a new type literal. Derives represented class from type
-   * parameter.
+   * Constructs a new type literal. Derives represented class from type parameter.
    *
-   * <p>Clients create an empty anonymous subclass. Doing so embeds the type
-   * parameter in the anonymous class's type hierarchy so we can reconstitute it
-   * at runtime despite erasure, for example:
-   * <p>
-   * {@code new TypeToken<List<String>>() {}}
+   * <p>Clients create an empty anonymous subclass. Doing so embeds the type parameter in the
+   * anonymous class's type hierarchy so we can reconstitute it at runtime despite erasure, for
+   * example:
    *
-   * @throws IllegalArgumentException
-   *   If the anonymous {@code TypeToken} subclass captures a type variable,
-   *   for example {@code TypeToken<List<T>>}. See the {@code TypeToken}
-   *   class documentation for more details.
+   * <p>{@code new TypeToken<List<String>>() {}}
+   *
+   * @throws IllegalArgumentException If the anonymous {@code TypeToken} subclass captures a type
+   *     variable, for example {@code TypeToken<List<T>>}. See the {@code TypeToken} class
+   *     documentation for more details.
    */
   @SuppressWarnings("unchecked")
   protected TypeToken() {
@@ -82,9 +76,7 @@ public class TypeToken<T> {
     this.hashCode = type.hashCode();
   }
 
-  /**
-   * Unsafe. Constructs a type literal manually.
-   */
+  /** Unsafe. Constructs a type literal manually. */
   @SuppressWarnings("unchecked")
   private TypeToken(Type type) {
     this.type = $Gson$Types.canonicalize(Objects.requireNonNull(type));
@@ -97,9 +89,8 @@ public class TypeToken<T> {
   }
 
   /**
-   * Verifies that {@code this} is an instance of a direct subclass of TypeToken and
-   * returns the type argument for {@code T} in {@link $Gson$Types#canonicalize
-   * canonical form}.
+   * Verifies that {@code this} is an instance of a direct subclass of TypeToken and returns the
+   * type argument for {@code T} in {@link $Gson$Types#canonicalize canonical form}.
    */
   private Type getTypeTokenTypeArgument() {
     Type superclass = getClass().getGenericSuperclass();
@@ -116,10 +107,11 @@ public class TypeToken<T> {
     }
     // Check for raw TypeToken as superclass
     else if (superclass == TypeToken.class) {
-      throw new IllegalStateException("TypeToken must be created with a type argument: new TypeToken<...>() {};"
-          + " When using code shrinkers (ProGuard, R8, ...) make sure that generic signatures are preserved."
-          + "\nSee " + TroubleshootingGuide.createUrl("type-token-raw")
-      );
+      throw new IllegalStateException(
+          "TypeToken must be created with a type argument: new TypeToken<...>() {}; When using code"
+              + " shrinkers (ProGuard, R8, ...) make sure that generic signatures are preserved."
+              + "\nSee "
+              + TroubleshootingGuide.createUrl("type-token-raw"));
     }
 
     // User created subclass of subclass of TypeToken
@@ -129,9 +121,13 @@ public class TypeToken<T> {
   private static void verifyNoTypeVariable(Type type) {
     if (type instanceof TypeVariable) {
       TypeVariable<?> typeVariable = (TypeVariable<?>) type;
-      throw new IllegalArgumentException("TypeToken type argument must not contain a type variable; captured type variable "
-          + typeVariable.getName() + " declared by " + typeVariable.getGenericDeclaration()
-          + "\nSee " + TroubleshootingGuide.createUrl("typetoken-type-variable"));
+      throw new IllegalArgumentException(
+          "TypeToken type argument must not contain a type variable; captured type variable "
+              + typeVariable.getName()
+              + " declared by "
+              + typeVariable.getGenericDeclaration()
+              + "\nSee "
+              + TroubleshootingGuide.createUrl("typetoken-type-variable"));
     } else if (type instanceof GenericArrayType) {
       verifyNoTypeVariable(((GenericArrayType) type).getGenericComponentType());
     } else if (type instanceof ParameterizedType) {
@@ -153,22 +149,20 @@ public class TypeToken<T> {
         verifyNoTypeVariable(bound);
       }
     } else if (type == null) {
-      // Occurs in Eclipse IDE and certain Java versions (e.g. Java 11.0.18) when capturing type variable
-      // declared by method of local class, see https://github.com/eclipse-jdt/eclipse.jdt.core/issues/975
-      throw new IllegalArgumentException("TypeToken captured `null` as type argument; probably a compiler / runtime bug");
+      // Occurs in Eclipse IDE and certain Java versions (e.g. Java 11.0.18) when capturing type
+      // variable declared by method of local class, see
+      // https://github.com/eclipse-jdt/eclipse.jdt.core/issues/975
+      throw new IllegalArgumentException(
+          "TypeToken captured `null` as type argument; probably a compiler / runtime bug");
     }
   }
 
-  /**
-   * Returns the raw (non-generic) type for this type.
-   */
+  /** Returns the raw (non-generic) type for this type. */
   public final Class<? super T> getRawType() {
     return rawType;
   }
 
-  /**
-   * Gets underlying {@code Type} instance.
-   */
+  /** Gets underlying {@code Type} instance. */
   public final Type getType() {
     return type;
   }
@@ -176,8 +170,7 @@ public class TypeToken<T> {
   /**
    * Check if this type is assignable from the given class object.
    *
-   * @deprecated this implementation may be inconsistent with javac for types
-   *     with wildcards.
+   * @deprecated this implementation may be inconsistent with javac for types with wildcards.
    */
   @Deprecated
   public boolean isAssignableFrom(Class<?> cls) {
@@ -187,8 +180,7 @@ public class TypeToken<T> {
   /**
    * Check if this type is assignable from the given Type.
    *
-   * @deprecated this implementation may be inconsistent with javac for types
-   *     with wildcards.
+   * @deprecated this implementation may be inconsistent with javac for types with wildcards.
    */
   @Deprecated
   public boolean isAssignableFrom(Type from) {
@@ -203,13 +195,12 @@ public class TypeToken<T> {
     if (type instanceof Class<?>) {
       return rawType.isAssignableFrom($Gson$Types.getRawType(from));
     } else if (type instanceof ParameterizedType) {
-      return isAssignableFrom(from, (ParameterizedType) type,
-          new HashMap<String, Type>());
+      return isAssignableFrom(from, (ParameterizedType) type, new HashMap<String, Type>());
     } else if (type instanceof GenericArrayType) {
       return rawType.isAssignableFrom($Gson$Types.getRawType(from))
           && isAssignableFrom(from, (GenericArrayType) type);
     } else {
-      throw buildUnexpectedTypeError(
+      throw buildUnsupportedTypeException(
           type, Class.class, ParameterizedType.class, GenericArrayType.class);
     }
   }
@@ -217,8 +208,7 @@ public class TypeToken<T> {
   /**
    * Check if this type is assignable from the given type token.
    *
-   * @deprecated this implementation may be inconsistent with javac for types
-   *     with wildcards.
+   * @deprecated this implementation may be inconsistent with javac for types with wildcards.
    */
   @Deprecated
   public boolean isAssignableFrom(TypeToken<?> token) {
@@ -226,8 +216,8 @@ public class TypeToken<T> {
   }
 
   /**
-   * Private helper function that performs some assignability checks for
-   * the provided GenericArrayType.
+   * Private helper function that performs some assignability checks for the provided
+   * GenericArrayType.
    */
   private static boolean isAssignableFrom(Type from, GenericArrayType to) {
     Type toGenericComponentType = to.getGenericComponentType();
@@ -242,20 +232,17 @@ public class TypeToken<T> {
         }
         t = classType;
       }
-      return isAssignableFrom(t, (ParameterizedType) toGenericComponentType,
-          new HashMap<String, Type>());
+      return isAssignableFrom(
+          t, (ParameterizedType) toGenericComponentType, new HashMap<String, Type>());
     }
     // No generic defined on "to"; therefore, return true and let other
     // checks determine assignability
     return true;
   }
 
-  /**
-   * Private recursive helper function to actually do the type-safe checking
-   * of assignability.
-   */
-  private static boolean isAssignableFrom(Type from, ParameterizedType to,
-      Map<String, Type> typeVarMap) {
+  /** Private recursive helper function to actually do the type-safe checking of assignability. */
+  private static boolean isAssignableFrom(
+      Type from, ParameterizedType to, Map<String, Type> typeVarMap) {
 
     if (from == null) {
       return false;
@@ -304,11 +291,11 @@ public class TypeToken<T> {
   }
 
   /**
-   * Checks if two parameterized types are exactly equal, under the variable
-   * replacement described in the typeVarMap.
+   * Checks if two parameterized types are exactly equal, under the variable replacement described
+   * in the typeVarMap.
    */
-  private static boolean typeEquals(ParameterizedType from,
-      ParameterizedType to, Map<String, Type> typeVarMap) {
+  private static boolean typeEquals(
+      ParameterizedType from, ParameterizedType to, Map<String, Type> typeVarMap) {
     if (from.getRawType().equals(to.getRawType())) {
       Type[] fromArgs = from.getActualTypeArguments();
       Type[] toArgs = to.getActualTypeArguments();
@@ -322,55 +309,54 @@ public class TypeToken<T> {
     return false;
   }
 
-  private static AssertionError buildUnexpectedTypeError(
+  private static IllegalArgumentException buildUnsupportedTypeException(
       Type token, Class<?>... expected) {
 
     // Build exception message
-    StringBuilder exceptionMessage =
-        new StringBuilder("Unexpected type. Expected one of: ");
+    StringBuilder exceptionMessage = new StringBuilder("Unsupported type, expected one of: ");
     for (Class<?> clazz : expected) {
       exceptionMessage.append(clazz.getName()).append(", ");
     }
-    exceptionMessage.append("but got: ").append(token.getClass().getName())
-        .append(", for type token: ").append(token.toString()).append('.');
+    exceptionMessage
+        .append("but got: ")
+        .append(token.getClass().getName())
+        .append(", for type token: ")
+        .append(token.toString());
 
-    return new AssertionError(exceptionMessage.toString());
+    return new IllegalArgumentException(exceptionMessage.toString());
   }
 
   /**
-   * Checks if two types are the same or are equivalent under a variable mapping
-   * given in the type map that was provided.
+   * Checks if two types are the same or are equivalent under a variable mapping given in the type
+   * map that was provided.
    */
   private static boolean matches(Type from, Type to, Map<String, Type> typeMap) {
     return to.equals(from)
         || (from instanceof TypeVariable
-        && to.equals(typeMap.get(((TypeVariable<?>) from).getName())));
-
+            && to.equals(typeMap.get(((TypeVariable<?>) from).getName())));
   }
 
-  @Override public final int hashCode() {
+  @Override
+  public final int hashCode() {
     return this.hashCode;
   }
 
-  @Override public final boolean equals(Object o) {
-    return o instanceof TypeToken<?>
-        && $Gson$Types.equals(type, ((TypeToken<?>) o).type);
+  @Override
+  public final boolean equals(Object o) {
+    return o instanceof TypeToken<?> && $Gson$Types.equals(type, ((TypeToken<?>) o).type);
   }
 
-  @Override public final String toString() {
+  @Override
+  public final String toString() {
     return $Gson$Types.typeToString(type);
   }
 
-  /**
-   * Gets type literal for the given {@code Type} instance.
-   */
+  /** Gets type literal for the given {@code Type} instance. */
   public static TypeToken<?> get(Type type) {
     return new TypeToken<>(type);
   }
 
-  /**
-   * Gets type literal for the given {@code Class} instance.
-   */
+  /** Gets type literal for the given {@code Class} instance. */
   public static <T> TypeToken<T> get(Class<T> type) {
     return new TypeToken<>(type);
   }
@@ -380,20 +366,21 @@ public class TypeToken<T> {
    * {@code rawType}. This is mainly intended for situations where the type arguments are not
    * available at compile time. The following example shows how a type token for {@code Map<K, V>}
    * can be created:
+   *
    * <pre>{@code
    * Class<K> keyClass = ...;
    * Class<V> valueClass = ...;
    * TypeToken<?> mapTypeToken = TypeToken.getParameterized(Map.class, keyClass, valueClass);
    * }</pre>
+   *
    * As seen here the result is a {@code TypeToken<?>}; this method cannot provide any type-safety,
    * and care must be taken to pass in the correct number of type arguments.
    *
    * <p>If {@code rawType} is a non-generic class and no type arguments are provided, this method
    * simply delegates to {@link #get(Class)} and creates a {@code TypeToken(Class)}.
    *
-   * @throws IllegalArgumentException
-   *   If {@code rawType} is not of type {@code Class}, or if the type arguments are invalid for
-   *   the raw type
+   * @throws IllegalArgumentException If {@code rawType} is not of type {@code Class}, or if the
+   *     type arguments are invalid for the raw type
    */
   public static TypeToken<?> getParameterized(Type rawType, Type... typeArguments) {
     Objects.requireNonNull(rawType);
@@ -411,8 +398,12 @@ public class TypeToken<T> {
     int expectedArgsCount = typeVariables.length;
     int actualArgsCount = typeArguments.length;
     if (actualArgsCount != expectedArgsCount) {
-      throw new IllegalArgumentException(rawClass.getName() + " requires " + expectedArgsCount +
-          " type arguments, but got " + actualArgsCount);
+      throw new IllegalArgumentException(
+          rawClass.getName()
+              + " requires "
+              + expectedArgsCount
+              + " type arguments, but got "
+              + actualArgsCount);
     }
 
     // For legacy reasons create a TypeToken(Class) if the type is not generic
@@ -422,12 +413,15 @@ public class TypeToken<T> {
 
     // Check for this here to avoid misleading exception thrown by ParameterizedTypeImpl
     if ($Gson$Types.requiresOwnerType(rawType)) {
-      throw new IllegalArgumentException("Raw type " + rawClass.getName() + " is not supported because"
-          + " it requires specifying an owner type");
+      throw new IllegalArgumentException(
+          "Raw type "
+              + rawClass.getName()
+              + " is not supported because it requires specifying an owner type");
     }
 
     for (int i = 0; i < expectedArgsCount; i++) {
-      Type typeArgument = Objects.requireNonNull(typeArguments[i], "Type argument must not be null");
+      Type typeArgument =
+          Objects.requireNonNull(typeArguments[i], "Type argument must not be null");
       Class<?> rawTypeArgument = $Gson$Types.getRawType(typeArgument);
       TypeVariable<?> typeVariable = typeVariables[i];
 
@@ -435,8 +429,13 @@ public class TypeToken<T> {
         Class<?> rawBound = $Gson$Types.getRawType(bound);
 
         if (!rawBound.isAssignableFrom(rawTypeArgument)) {
-          throw new IllegalArgumentException("Type argument " + typeArgument + " does not satisfy bounds"
-              + " for type variable " + typeVariable + " declared by " + rawType);
+          throw new IllegalArgumentException(
+              "Type argument "
+                  + typeArgument
+                  + " does not satisfy bounds for type variable "
+                  + typeVariable
+                  + " declared by "
+                  + rawType);
         }
       }
     }

gson/src/main/java/com/google/gson/stream/JsonScope.java

@@ -23,49 +23,29 @@ package com.google.gson.stream;
  * @since 1.6
  */
 final class JsonScope {
+  private JsonScope() {}
 
-    /**
-     * An array with no elements requires no separators or newlines before
-     * it is closed.
-     */
-    static final int EMPTY_ARRAY = 1;
+  /** An array with no elements requires no separator before the next element. */
+  static final int EMPTY_ARRAY = 1;
 
-    /**
-     * An array with at least one value requires a comma and newline before
-     * the next element.
-     */
-    static final int NONEMPTY_ARRAY = 2;
+  /** An array with at least one value requires a separator before the next element. */
+  static final int NONEMPTY_ARRAY = 2;
 
-    /**
-     * An object with no name/value pairs requires no separators or newlines
-     * before it is closed.
-     */
-    static final int EMPTY_OBJECT = 3;
+  /** An object with no name/value pairs requires no separator before the next element. */
+  static final int EMPTY_OBJECT = 3;
 
-    /**
-     * An object whose most recent element is a key. The next element must
-     * be a value.
-     */
-    static final int DANGLING_NAME = 4;
+  /** An object whose most recent element is a key. The next element must be a value. */
+  static final int DANGLING_NAME = 4;
 
-    /**
-     * An object with at least one name/value pair requires a comma and
-     * newline before the next element.
-     */
-    static final int NONEMPTY_OBJECT = 5;
+  /** An object with at least one name/value pair requires a separator before the next element. */
+  static final int NONEMPTY_OBJECT = 5;
 
-    /**
-     * No object or array has been started.
-     */
-    static final int EMPTY_DOCUMENT = 6;
+  /** No top-level value has been started yet. */
+  static final int EMPTY_DOCUMENT = 6;
 
-    /**
-     * A document with at an array or object.
-     */
-    static final int NONEMPTY_DOCUMENT = 7;
+  /** A top-level value has already been started. */
+  static final int NONEMPTY_DOCUMENT = 7;
 
-    /**
-     * A document that's been closed and cannot be accessed.
-     */
-    static final int CLOSED = 8;
+  /** A document that's been closed and cannot be accessed. */
+  static final int CLOSED = 8;
 }

gson/src/main/java/com/google/gson/stream/JsonToken.java

@@ -25,61 +25,52 @@ package com.google.gson.stream;
 public enum JsonToken {
 
   /**
-   * The opening of a JSON array. Written using {@link JsonWriter#beginArray}
-   * and read using {@link JsonReader#beginArray}.
+   * The opening of a JSON array. Written using {@link JsonWriter#beginArray} and read using {@link
+   * JsonReader#beginArray}.
    */
   BEGIN_ARRAY,
 
   /**
-   * The closing of a JSON array. Written using {@link JsonWriter#endArray}
-   * and read using {@link JsonReader#endArray}.
+   * The closing of a JSON array. Written using {@link JsonWriter#endArray} and read using {@link
+   * JsonReader#endArray}.
    */
   END_ARRAY,
 
   /**
-   * The opening of a JSON object. Written using {@link JsonWriter#beginObject}
-   * and read using {@link JsonReader#beginObject}.
+   * The opening of a JSON object. Written using {@link JsonWriter#beginObject} and read using
+   * {@link JsonReader#beginObject}.
    */
   BEGIN_OBJECT,
 
   /**
-   * The closing of a JSON object. Written using {@link JsonWriter#endObject}
-   * and read using {@link JsonReader#endObject}.
+   * The closing of a JSON object. Written using {@link JsonWriter#endObject} and read using {@link
+   * JsonReader#endObject}.
    */
   END_OBJECT,
 
   /**
-   * A JSON property name. Within objects, tokens alternate between names and
-   * their values. Written using {@link JsonWriter#name} and read using {@link
-   * JsonReader#nextName}
+   * A JSON property name. Within objects, tokens alternate between names and their values. Written
+   * using {@link JsonWriter#name} and read using {@link JsonReader#nextName}
    */
   NAME,
 
-  /**
-   * A JSON string.
-   */
+  /** A JSON string. */
   STRING,
 
   /**
-   * A JSON number represented in this API by a Java {@code double}, {@code
-   * long}, or {@code int}.
+   * A JSON number represented in this API by a Java {@code double}, {@code long}, or {@code int}.
    */
   NUMBER,
 
-  /**
-   * A JSON {@code true} or {@code false}.
-   */
+  /** A JSON {@code true} or {@code false}. */
   BOOLEAN,
 
-  /**
-   * A JSON {@code null}.
-   */
+  /** A JSON {@code null}. */
   NULL,
 
   /**
-   * The end of the JSON stream. This sentinel value is returned by {@link
-   * JsonReader#peek()} to signal that the JSON-encoded value has no more
-   * tokens.
+   * The end of the JSON stream. This sentinel value is returned by {@link JsonReader#peek()} to
+   * signal that the JSON-encoded value has no more tokens.
    */
   END_DOCUMENT
 }

gson/src/main/java/com/google/gson/stream/JsonTreeReader.java

@@ -31,20 +31,23 @@ import java.util.Iterator;
 import java.util.Map;
 
 /**
- * This reader walks the elements of a JsonElement as if it was coming from a
- * character stream.
+ * This reader walks the elements of a JsonElement as if it was coming from a character stream.
  *
  * @author Jesse Wilson
  */
 public final class JsonTreeReader extends JsonReader {
-  private static final Reader UNREADABLE_READER = new Reader() {
-    @Override public int read(char[] buffer, int offset, int count) {
-      throw new AssertionError();
-    }
-    @Override public void close() {
-      throw new AssertionError();
-    }
-  };
+  private static final Reader UNREADABLE_READER =
+      new Reader() {
+        @Override
+        public int read(char[] buffer, int offset, int count) {
+          throw new AssertionError();
+        }
+
+        @Override
+        public void close() {
+          throw new AssertionError();
+        }
+      };
   private static final Object SENTINEL_CLOSED = new Object();
 
   /*
@@ -69,14 +72,16 @@ public final class JsonTreeReader extends JsonReader {
     push(element);
   }
 
-  @Override public void beginArray() throws IOException {
+  @Override
+  public void beginArray() throws IOException {
     expect(JsonToken.BEGIN_ARRAY);
     JsonArray array = (JsonArray) peekStack();
     push(array.iterator());
     pathIndices[stackSize - 1] = 0;
   }
 
-  @Override public void endArray() throws IOException {
+  @Override
+  public void endArray() throws IOException {
     expect(JsonToken.END_ARRAY);
     popStack(); // empty iterator
     popStack(); // array
@@ -85,13 +90,15 @@ public final class JsonTreeReader extends JsonReader {
     }
   }
 
-  @Override public void beginObject() throws IOException {
+  @Override
+  public void beginObject() throws IOException {
     expect(JsonToken.BEGIN_OBJECT);
     JsonObject object = (JsonObject) peekStack();
     push(object.entrySet().iterator());
   }
 
-  @Override public void endObject() throws IOException {
+  @Override
+  public void endObject() throws IOException {
     expect(JsonToken.END_OBJECT);
     pathNames[stackSize - 1] = null; // Free the last path name so that it can be garbage collected
     popStack(); // empty iterator
@@ -101,12 +108,16 @@ public final class JsonTreeReader extends JsonReader {
     }
   }
 
-  @Override public boolean hasNext() throws IOException {
+  @Override
+  public boolean hasNext() throws IOException {
     JsonToken token = peek();
-    return token != JsonToken.END_OBJECT && token != JsonToken.END_ARRAY && token != JsonToken.END_DOCUMENT;
+    return token != JsonToken.END_OBJECT
+        && token != JsonToken.END_ARRAY
+        && token != JsonToken.END_DOCUMENT;
   }
 
-  @Override public JsonToken peek() throws IOException {
+  @Override
+  public JsonToken peek() throws IOException {
     if (stackSize == 0) {
       return JsonToken.END_DOCUMENT;
     }
@@ -145,7 +156,8 @@ public final class JsonTreeReader extends JsonReader {
     } else if (o == SENTINEL_CLOSED) {
       throw new IllegalStateException("JsonReader is closed");
     } else {
-      throw new MalformedJsonException("Custom JsonElement subclass " + o.getClass().getName() + " is not supported");
+      throw new MalformedJsonException(
+          "Custom JsonElement subclass " + o.getClass().getName() + " is not supported");
     }
   }
 
@@ -176,11 +188,13 @@ public final class JsonTreeReader extends JsonReader {
     return result;
   }
 
-  @Override public String nextName() throws IOException {
+  @Override
+  public String nextName() throws IOException {
     return nextName(false);
   }
 
-  @Override public String nextString() throws IOException {
+  @Override
+  public String nextString() throws IOException {
     JsonToken token = peek();
     if (token != JsonToken.STRING && token != JsonToken.NUMBER) {
       throw new IllegalStateException(
@@ -193,7 +207,8 @@ public final class JsonTreeReader extends JsonReader {
     return result;
   }
 
-  @Override public boolean nextBoolean() throws IOException {
+  @Override
+  public boolean nextBoolean() throws IOException {
     expect(JsonToken.BOOLEAN);
     boolean result = ((JsonPrimitive) popStack()).getAsBoolean();
     if (stackSize > 0) {
@@ -202,7 +217,8 @@ public final class JsonTreeReader extends JsonReader {
     return result;
   }
 
-  @Override public void nextNull() throws IOException {
+  @Override
+  public void nextNull() throws IOException {
     expect(JsonToken.NULL);
     popStack();
     if (stackSize > 0) {
@@ -210,7 +226,8 @@ public final class JsonTreeReader extends JsonReader {
     }
   }
 
-  @Override public double nextDouble() throws IOException {
+  @Override
+  public double nextDouble() throws IOException {
     JsonToken token = peek();
     if (token != JsonToken.NUMBER && token != JsonToken.STRING) {
       throw new IllegalStateException(
@@ -227,7 +244,8 @@ public final class JsonTreeReader extends JsonReader {
     return result;
   }
 
-  @Override public long nextLong() throws IOException {
+  @Override
+  public long nextLong() throws IOException {
     JsonToken token = peek();
     if (token != JsonToken.NUMBER && token != JsonToken.STRING) {
       throw new IllegalStateException(
@@ -241,7 +259,8 @@ public final class JsonTreeReader extends JsonReader {
     return result;
   }
 
-  @Override public int nextInt() throws IOException {
+  @Override
+  public int nextInt() throws IOException {
     JsonToken token = peek();
     if (token != JsonToken.NUMBER && token != JsonToken.STRING) {
       throw new IllegalStateException(
@@ -268,12 +287,14 @@ public final class JsonTreeReader extends JsonReader {
     return element;
   }
 
-  @Override public void close() throws IOException {
-    stack = new Object[] { SENTINEL_CLOSED };
+  @Override
+  public void close() throws IOException {
+    stack = new Object[] {SENTINEL_CLOSED};
     stackSize = 1;
   }
 
-  @Override public void skipValue() throws IOException {
+  @Override
+  public void skipValue() throws IOException {
     JsonToken peeked = peek();
     switch (peeked) {
       case NAME:
@@ -297,7 +318,8 @@ public final class JsonTreeReader extends JsonReader {
     }
   }
 
-  @Override public String toString() {
+  @Override
+  public String toString() {
     return getClass().getSimpleName() + locationString();
   }
 
@@ -345,12 +367,14 @@ public final class JsonTreeReader extends JsonReader {
     return result.toString();
   }
 
-  @Override public String getPreviousPath() {
-    return getPath(true);
+  @Override
+  public String getPath() {
+    return getPath(false);
   }
 
-  @Override public String getPath() {
-    return getPath(false);
+  @Override
+  public String getPreviousPath() {
+    return getPath(true);
   }
 
   private String locationString() {

gson/src/main/java/com/google/gson/stream/JsonTreeWriter.java

@@ -28,21 +28,26 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
-/**
- * This writer creates a JsonElement.
- */
+/** This writer creates a JsonElement. */
 public final class JsonTreeWriter extends JsonWriter {
-  private static final Writer UNWRITABLE_WRITER = new Writer() {
-    @Override public void write(char[] buffer, int offset, int counter) {
-      throw new AssertionError();
-    }
-    @Override public void flush() {
-      throw new AssertionError();
-    }
-    @Override public void close() {
-      throw new AssertionError();
-    }
-  };
+  private static final Writer UNWRITABLE_WRITER =
+      new Writer() {
+        @Override
+        public void write(char[] buffer, int offset, int counter) {
+          throw new AssertionError();
+        }
+
+        @Override
+        public void flush() {
+          throw new AssertionError();
+        }
+
+        @Override
+        public void close() {
+          throw new AssertionError();
+        }
+      };
+
   /** Added to the top of the stack when this writer is closed to cause following ops to fail. */
   private static final JsonPrimitive SENTINEL_CLOSED = new JsonPrimitive("closed");
 
@@ -59,9 +64,7 @@ public final class JsonTreeWriter extends JsonWriter {
     super(UNWRITABLE_WRITER);
   }
 
-  /**
-   * Returns the top level object produced by this writer.
-   */
+  /** Returns the top level object produced by this writer. */
   public JsonElement get() {
     if (!stack.isEmpty()) {
       throw new IllegalStateException("Expected one JSON element but was " + stack);
@@ -97,14 +100,16 @@ public final class JsonTreeWriter extends JsonWriter {
     }
   }
 
-  @Override public JsonWriter beginArray() throws IOException {
+  @Override
+  public JsonWriter beginArray() throws IOException {
     JsonArray array = new JsonArray();
     put(array);
     stack.add(array);
     return this;
   }
 
-  @Override public JsonWriter endArray() throws IOException {
+  @Override
+  public JsonWriter endArray() throws IOException {
     if (stack.isEmpty() || pendingName != null) {
       throw new IllegalStateException();
     }
@@ -116,14 +121,16 @@ public final class JsonTreeWriter extends JsonWriter {
     throw new IllegalStateException();
   }
 
-  @Override public JsonWriter beginObject() throws IOException {
+  @Override
+  public JsonWriter beginObject() throws IOException {
     JsonObject object = new JsonObject();
     put(object);
     stack.add(object);
     return this;
   }
 
-  @Override public JsonWriter endObject() throws IOException {
+  @Override
+  public JsonWriter endObject() throws IOException {
     if (stack.isEmpty() || pendingName != null) {
       throw new IllegalStateException();
     }
@@ -135,7 +142,8 @@ public final class JsonTreeWriter extends JsonWriter {
     throw new IllegalStateException();
   }
 
-  @Override public JsonWriter name(String name) throws IOException {
+  @Override
+  public JsonWriter name(String name) throws IOException {
     Objects.requireNonNull(name, "name == null");
     if (stack.isEmpty() || pendingName != null) {
       throw new IllegalStateException("Did not expect a name");
@@ -148,7 +156,8 @@ public final class JsonTreeWriter extends JsonWriter {
     throw new IllegalStateException("Please begin an object before writing a name.");
   }
 
-  @Override public JsonWriter value(String value) throws IOException {
+  @Override
+  public JsonWriter value(String value) throws IOException {
     if (value == null) {
       return nullValue();
     }
@@ -156,21 +165,14 @@ public final class JsonTreeWriter extends JsonWriter {
     return this;
   }
 
-  @Override public JsonWriter jsonValue(String value) throws IOException {
-    throw new UnsupportedOperationException();
-  }
-
-  @Override public JsonWriter nullValue() throws IOException {
-    put(JsonNull.INSTANCE);
-    return this;
-  }
-
-  @Override public JsonWriter value(boolean value) throws IOException {
+  @Override
+  public JsonWriter value(boolean value) throws IOException {
     put(new JsonPrimitive(value));
     return this;
   }
 
-  @Override public JsonWriter value(Boolean value) throws IOException {
+  @Override
+  public JsonWriter value(Boolean value) throws IOException {
     if (value == null) {
       return nullValue();
     }
@@ -178,7 +180,8 @@ public final class JsonTreeWriter extends JsonWriter {
     return this;
   }
 
-  @Override public JsonWriter value(float value) throws IOException {
+  @Override
+  public JsonWriter value(float value) throws IOException {
     if (!isLenient() && (Float.isNaN(value) || Float.isInfinite(value))) {
       throw new IllegalArgumentException("JSON forbids NaN and infinities: " + value);
     }
@@ -186,7 +189,8 @@ public final class JsonTreeWriter extends JsonWriter {
     return this;
   }
 
-  @Override public JsonWriter value(double value) throws IOException {
+  @Override
+  public JsonWriter value(double value) throws IOException {
     if (!isLenient() && (Double.isNaN(value) || Double.isInfinite(value))) {
       throw new IllegalArgumentException("JSON forbids NaN and infinities: " + value);
     }
@@ -194,12 +198,14 @@ public final class JsonTreeWriter extends JsonWriter {
     return this;
   }
 
-  @Override public JsonWriter value(long value) throws IOException {
+  @Override
+  public JsonWriter value(long value) throws IOException {
     put(new JsonPrimitive(value));
     return this;
   }
 
-  @Override public JsonWriter value(Number value) throws IOException {
+  @Override
+  public JsonWriter value(Number value) throws IOException {
     if (value == null) {
       return nullValue();
     }
@@ -215,10 +221,22 @@ public final class JsonTreeWriter extends JsonWriter {
     return this;
   }
 
-  @Override public void flush() throws IOException {
+  @Override
+  public JsonWriter nullValue() throws IOException {
+    put(JsonNull.INSTANCE);
+    return this;
   }
 
-  @Override public void close() throws IOException {
+  @Override
+  public JsonWriter jsonValue(String value) throws IOException {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void flush() throws IOException {}
+
+  @Override
+  public void close() throws IOException {
     if (!stack.isEmpty()) {
       throw new IOException("Incomplete document");
     }

gson/src/main/java/com/google/gson/stream/JsonWriter.java

@@ -30,6 +30,8 @@ import com.google.gson.FormattingStyle;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.Strictness;
+import com.google.gson.util.StringEscapeUtil;
+
 import java.io.Closeable;
 import java.io.Flushable;
 import java.io.IOException;
@@ -42,43 +44,46 @@ import java.util.concurrent.atomic.AtomicLong;
 import java.util.regex.Pattern;
 
 /**
- * Writes a JSON (<a href="https://www.ietf.org/rfc/rfc8259.txt">RFC 8259</a>)
- * encoded value to a stream, one token at a time. The stream includes both
- * literal values (strings, numbers, booleans and nulls) as well as the begin
- * and end delimiters of objects and arrays.
+ * Writes a JSON (<a href="https://www.ietf.org/rfc/rfc8259.txt">RFC 8259</a>) encoded value to a
+ * stream, one token at a time. The stream includes both literal values (strings, numbers, booleans
+ * and nulls) as well as the begin and end delimiters of objects and arrays.
  *
  * <h2>Encoding JSON</h2>
- * To encode your data as JSON, create a new {@code JsonWriter}. Call methods
- * on the writer as you walk the structure's contents, nesting arrays and objects
- * as necessary:
+ *
+ * To encode your data as JSON, create a new {@code JsonWriter}. Call methods on the writer as you
+ * walk the structure's contents, nesting arrays and objects as necessary:
+ *
  * <ul>
- *   <li>To write <strong>arrays</strong>, first call {@link #beginArray()}.
- *       Write each of the array's elements with the appropriate {@link #value}
- *       methods or by nesting other arrays and objects. Finally close the array
- *       using {@link #endArray()}.
- *   <li>To write <strong>objects</strong>, first call {@link #beginObject()}.
- *       Write each of the object's properties by alternating calls to
- *       {@link #name} with the property's value. Write property values with the
- *       appropriate {@link #value} method or by nesting other objects or arrays.
- *       Finally close the object using {@link #endObject()}.
+ *   <li>To write <strong>arrays</strong>, first call {@link #beginArray()}. Write each of the
+ *       array's elements with the appropriate {@link #value} methods or by nesting other arrays and
+ *       objects. Finally close the array using {@link #endArray()}.
+ *   <li>To write <strong>objects</strong>, first call {@link #beginObject()}. Write each of the
+ *       object's properties by alternating calls to {@link #name} with the property's value. Write
+ *       property values with the appropriate {@link #value} method or by nesting other objects or
+ *       arrays. Finally close the object using {@link #endObject()}.
  * </ul>
  *
  * <h2>Configuration</h2>
+ *
  * The behavior of this writer can be customized with the following methods:
+ *
  * <ul>
- *   <li>{@link #setFormattingStyle(FormattingStyle)}, the default is {@link FormattingStyle#COMPACT}
- *   <li>{@link #setHtmlSafe(boolean)}, by default HTML characters are not escaped
- *       in the JSON output
+ *   <li>{@link #setFormattingStyle(FormattingStyle)}, the default is {@link
+ *       FormattingStyle#COMPACT}
+ *   <li>{@link #setHtmlSafe(boolean)}, by default HTML characters are not escaped in the JSON
+ *       output
  *   <li>{@link #setStrictness(Strictness)}, the default is {@link Strictness#LEGACY_STRICT}
  *   <li>{@link #setSerializeNulls(boolean)}, by default {@code null} is serialized
  * </ul>
  *
- * The default configuration of {@code JsonWriter} instances used internally by
- * the {@link Gson} class differs, and can be adjusted with the various
- * {@link GsonBuilder} methods.
+ * The default configuration of {@code JsonWriter} instances used internally by the {@link Gson}
+ * class differs, and can be adjusted with the various {@link GsonBuilder} methods.
  *
  * <h2>Example</h2>
- * Suppose we'd like to encode a stream of messages such as the following: <pre> {@code
+ *
+ * Suppose we'd like to encode a stream of messages such as the following:
+ *
+ * <pre>{@code
  * [
  *   {
  *     "id": 912345678901,
@@ -98,56 +103,61 @@ import java.util.regex.Pattern;
  *       "followers_count": 2
  *     }
  *   }
- * ]}</pre>
- * This code encodes the above structure: <pre>   {@code
- *   public void writeJsonStream(OutputStream out, List<Message> messages) throws IOException {
- *     JsonWriter writer = new JsonWriter(new OutputStreamWriter(out, "UTF-8"));
- *     writer.setIndent("    ");
- *     writeMessagesArray(writer, messages);
- *     writer.close();
+ * ]
+ * }</pre>
+ *
+ * This code encodes the above structure:
+ *
+ * <pre>{@code
+ * public void writeJsonStream(OutputStream out, List<Message> messages) throws IOException {
+ *   JsonWriter writer = new JsonWriter(new OutputStreamWriter(out, "UTF-8"));
+ *   writer.setIndent("    ");
+ *   writeMessagesArray(writer, messages);
+ *   writer.close();
+ * }
+ *
+ * public void writeMessagesArray(JsonWriter writer, List<Message> messages) throws IOException {
+ *   writer.beginArray();
+ *   for (Message message : messages) {
+ *     writeMessage(writer, message);
  *   }
+ *   writer.endArray();
+ * }
  *
- *   public void writeMessagesArray(JsonWriter writer, List<Message> messages) throws IOException {
- *     writer.beginArray();
- *     for (Message message : messages) {
- *       writeMessage(writer, message);
- *     }
- *     writer.endArray();
+ * public void writeMessage(JsonWriter writer, Message message) throws IOException {
+ *   writer.beginObject();
+ *   writer.name("id").value(message.getId());
+ *   writer.name("text").value(message.getText());
+ *   if (message.getGeo() != null) {
+ *     writer.name("geo");
+ *     writeDoublesArray(writer, message.getGeo());
+ *   } else {
+ *     writer.name("geo").nullValue();
  *   }
+ *   writer.name("user");
+ *   writeUser(writer, message.getUser());
+ *   writer.endObject();
+ * }
  *
- *   public void writeMessage(JsonWriter writer, Message message) throws IOException {
- *     writer.beginObject();
- *     writer.name("id").value(message.getId());
- *     writer.name("text").value(message.getText());
- *     if (message.getGeo() != null) {
- *       writer.name("geo");
- *       writeDoublesArray(writer, message.getGeo());
- *     } else {
- *       writer.name("geo").nullValue();
- *     }
- *     writer.name("user");
- *     writeUser(writer, message.getUser());
- *     writer.endObject();
+ * public void writeUser(JsonWriter writer, User user) throws IOException {
+ *   writer.beginObject();
+ *   writer.name("name").value(user.getName());
+ *   writer.name("followers_count").value(user.getFollowersCount());
+ *   writer.endObject();
+ * }
+ *
+ * public void writeDoublesArray(JsonWriter writer, List<Double> doubles) throws IOException {
+ *   writer.beginArray();
+ *   for (Double value : doubles) {
+ *     writer.value(value);
  *   }
+ *   writer.endArray();
+ * }
+ * }</pre>
  *
- *   public void writeUser(JsonWriter writer, User user) throws IOException {
- *     writer.beginObject();
- *     writer.name("name").value(user.getName());
- *     writer.name("followers_count").value(user.getFollowersCount());
- *     writer.endObject();
- *   }
- *
- *   public void writeDoublesArray(JsonWriter writer, List<Double> doubles) throws IOException {
- *     writer.beginArray();
- *     for (Double value : doubles) {
- *       writer.value(value);
- *     }
- *     writer.endArray();
- *   }}</pre>
- *
- * <p>Each {@code JsonWriter} may be used to write a single JSON stream.
- * Instances of this class are not thread safe. Calls that would result in a
- * malformed JSON string will fail with an {@link IllegalStateException}.
+ * <p>Each {@code JsonWriter} may be used to write a single JSON stream. Instances of this class are
+ * not thread safe. Calls that would result in a malformed JSON string will fail with an {@link
+ * IllegalStateException}.
  *
  * @author Jesse Wilson
  * @since 1.6
@@ -155,45 +165,15 @@ import java.util.regex.Pattern;
 public class JsonWriter implements Closeable, Flushable {
 
   // Syntax as defined by https://datatracker.ietf.org/doc/html/rfc8259#section-6
-  private static final Pattern VALID_JSON_NUMBER_PATTERN = Pattern.compile("-?(?:0|[1-9][0-9]*)(?:\\.[0-9]+)?(?:[eE][-+]?[0-9]+)?");
-
-  /*
-   * From RFC 8259, "All Unicode characters may be placed within the
-   * quotation marks except for the characters that must be escaped:
-   * quotation mark, reverse solidus, and the control characters
-   * (U+0000 through U+001F)."
-   *
-   * We also escape '\u2028' and '\u2029', which JavaScript interprets as
-   * newline characters. This prevents eval() from failing with a syntax
-   * error. http://code.google.com/p/google-gson/issues/detail?id=341
-   */
-  private static final String[] REPLACEMENT_CHARS;
-  private static final String[] HTML_SAFE_REPLACEMENT_CHARS;
-  static {
-    REPLACEMENT_CHARS = new String[128];
-    for (int i = 0; i <= 0x1f; i++) {
-      REPLACEMENT_CHARS[i] = String.format("\\u%04x", i);
-    }
-    REPLACEMENT_CHARS['"'] = "\\\"";
-    REPLACEMENT_CHARS['\\'] = "\\\\";
-    REPLACEMENT_CHARS['\t'] = "\\t";
-    REPLACEMENT_CHARS['\b'] = "\\b";
-    REPLACEMENT_CHARS['\n'] = "\\n";
-    REPLACEMENT_CHARS['\r'] = "\\r";
-    REPLACEMENT_CHARS['\f'] = "\\f";
-    HTML_SAFE_REPLACEMENT_CHARS = REPLACEMENT_CHARS.clone();
-    HTML_SAFE_REPLACEMENT_CHARS['<'] = "\\u003c";
-    HTML_SAFE_REPLACEMENT_CHARS['>'] = "\\u003e";
-    HTML_SAFE_REPLACEMENT_CHARS['&'] = "\\u0026";
-    HTML_SAFE_REPLACEMENT_CHARS['='] = "\\u003d";
-    HTML_SAFE_REPLACEMENT_CHARS['\''] = "\\u0027";
-  }
+  private static final Pattern VALID_JSON_NUMBER_PATTERN =
+      Pattern.compile("-?(?:0|[1-9][0-9]*)(?:\\.[0-9]+)?(?:[eE][-+]?[0-9]+)?");
 
   /** The JSON output destination */
   private final Writer out;
 
   private int[] stack = new int[32];
   private int stackSize = 0;
+
   {
     push(EMPTY_DOCUMENT);
   }
@@ -220,9 +200,9 @@ public class JsonWriter implements Closeable, Flushable {
   private List<String> deferredComment = new LinkedList<>();
 
   /**
-   * Creates a new instance that writes a JSON-encoded stream to {@code out}.
-   * For best performance, ensure {@link Writer} is buffered; wrapping in
-   * {@link java.io.BufferedWriter BufferedWriter} if necessary.
+   * Creates a new instance that writes a JSON-encoded stream to {@code out}. For best performance,
+   * ensure {@link Writer} is buffered; wrapping in {@link java.io.BufferedWriter BufferedWriter} if
+   * necessary.
    */
   public JsonWriter(Writer out) {
     this.out = Objects.requireNonNull(out, "out == null");
@@ -230,16 +210,14 @@ public class JsonWriter implements Closeable, Flushable {
   }
 
   /**
-   * Sets the indentation string to be repeated for each level of indentation
-   * in the encoded document. If {@code indent.isEmpty()} the encoded document
-   * will be compact. Otherwise the encoded document will be more
-   * human-readable.
+   * Sets the indentation string to be repeated for each level of indentation in the encoded
+   * document. If {@code indent.isEmpty()} the encoded document will be compact. Otherwise the
+   * encoded document will be more human-readable.
    *
-   * <p>This is a convenience method which overwrites any previously
-   * {@linkplain #setFormattingStyle(FormattingStyle) set formatting style} with
-   * either {@link FormattingStyle#COMPACT} if the given indent string is
-   * empty, or {@link FormattingStyle#PRETTY} with the given indent if
-   * not empty.
+   * <p>This is a convenience method which overwrites any previously {@linkplain
+   * #setFormattingStyle(FormattingStyle) set formatting style} with either {@link
+   * FormattingStyle#COMPACT} if the given indent string is empty, or {@link FormattingStyle#PRETTY}
+   * with the given indent if not empty.
    *
    * @param indent a string containing only whitespace.
    */
@@ -254,9 +232,8 @@ public class JsonWriter implements Closeable, Flushable {
   /**
    * Sets the formatting style to be used in the encoded document.
    *
-   * <p>The formatting style specifies for example the indentation string to be
-   * repeated for each level of indentation, or the newline style, to accommodate
-   * various OS styles.</p>
+   * <p>The formatting style specifies for example the indentation string to be repeated for each
+   * level of indentation, or the newline style, to accommodate various OS styles.
    *
    * @param formattingStyle the formatting style to use, must not be {@code null}.
    * @since $next-version$
@@ -276,8 +253,8 @@ public class JsonWriter implements Closeable, Flushable {
       this.formattedColon = ":";
     }
 
-    this.usesEmptyNewlineAndIndent = this.formattingStyle.getNewline().isEmpty()
-        && this.formattingStyle.getIndent().isEmpty();
+    this.usesEmptyNewlineAndIndent =
+        this.formattingStyle.getNewline().isEmpty() && this.formattingStyle.getIndent().isEmpty();
   }
 
   /**
@@ -293,17 +270,20 @@ public class JsonWriter implements Closeable, Flushable {
   /**
    * Sets the strictness of this writer.
    *
-   * @deprecated Please use {@link #setStrictness(Strictness)} instead.
-   * {@code JsonWriter.setLenient(true)} should be replaced by {@code JsonWriter.setStrictness(Strictness.LENIENT)}
-   * and {@code JsonWriter.setLenient(false)} should be replaced by {@code JsonWriter.setStrictness(Strictness.LEGACY_STRICT)}.<br>
-   * However, if you used {@code setLenient(false)} before, you might prefer {@link Strictness#STRICT} now instead.
-   *
-   * @param lenient whether this writer should be lenient. If true, the strictness is set to {@link Strictness#LENIENT}.
-   *                If false, the strictness is set to {@link Strictness#LEGACY_STRICT}.
+   * @deprecated Please use {@link #setStrictness(Strictness)} instead. {@code
+   *     JsonWriter.setLenient(true)} should be replaced by {@code
+   *     JsonWriter.setStrictness(Strictness.LENIENT)} and {@code JsonWriter.setLenient(false)}
+   *     should be replaced by {@code JsonWriter.setStrictness(Strictness.LEGACY_STRICT)}.<br>
+   *     However, if you used {@code setLenient(false)} before, you might prefer {@link
+   *     Strictness#STRICT} now instead.
+   * @param lenient whether this writer should be lenient. If true, the strictness is set to {@link
+   *     Strictness#LENIENT}. If false, the strictness is set to {@link Strictness#LEGACY_STRICT}.
    * @see #setStrictness(Strictness)
    */
   @Deprecated
-  @SuppressWarnings("InlineMeSuggester") // Don't specify @InlineMe, so caller with `setLenient(false)` becomes aware of new Strictness.STRICT
+  // Don't specify @InlineMe, so caller with `setLenient(false)` becomes aware of new
+  // Strictness.STRICT
+  @SuppressWarnings("InlineMeSuggester")
   public final void setLenient(boolean lenient) {
     setStrictness(lenient ? Strictness.LENIENT : Strictness.LEGACY_STRICT);
     if (lenient) this.serializeSpecialFloatingPointValues = true;
@@ -320,19 +300,17 @@ public class JsonWriter implements Closeable, Flushable {
 
   /**
    * Configures how strict this writer is with regard to the syntax rules specified in <a
-   * href="https://www.ietf.org/rfc/rfc8259.txt">RFC 8259</a>. By default, {@link Strictness#LEGACY_STRICT} is used.
+   * href="https://www.ietf.org/rfc/rfc8259.txt">RFC 8259</a>. By default, {@link
+   * Strictness#LEGACY_STRICT} is used.
    *
    * <dl>
-   *     <dt>{@link Strictness#STRICT} &amp; {@link Strictness#LEGACY_STRICT}</dt>
-   *     <dd>
-   *         The behavior of these is currently identical. In these strictness modes, the writer only writes JSON
-   *         in accordance with RFC 8259.
-   *     </dd>
-   *     <dt>{@link Strictness#LENIENT}</dt>
-   *     <dd>
-   *         This mode relaxes the behavior of the writer to allow the writing of {@link Double#isNaN() NaNs}
-   *         and {@link Double#isInfinite() infinities}. It also allows writing multiple top level values.
-   *     </dd>
+   *   <dt>{@link Strictness#STRICT} &amp; {@link Strictness#LEGACY_STRICT}
+   *   <dd>The behavior of these is currently identical. In these strictness modes, the writer only
+   *       writes JSON in accordance with RFC 8259.
+   *   <dt>{@link Strictness#LENIENT}
+   *   <dd>This mode relaxes the behavior of the writer to allow the writing of {@link
+   *       Double#isNaN() NaNs} and {@link Double#isInfinite() infinities}. It also allows writing
+   *       multiple top level values.
    * </dl>
    *
    * @param strictness the new strictness of this writer. May not be {@code null}.
@@ -362,35 +340,33 @@ public class JsonWriter implements Closeable, Flushable {
   }
 
   /**
-   * Configures this writer to emit JSON that's safe for direct inclusion in HTML
-   * and XML documents. This escapes the HTML characters {@code <}, {@code >},
-   * {@code &} and {@code =} before writing them to the stream. Without this
-   * setting, your XML/HTML encoder should replace these characters with the
-   * corresponding escape sequences.
+   * Configures this writer to emit JSON that's safe for direct inclusion in HTML and XML documents.
+   * This escapes the HTML characters {@code <}, {@code >}, {@code &}, {@code =} and {@code '}
+   * before writing them to the stream. Without this setting, your XML/HTML encoder should replace
+   * these characters with the corresponding escape sequences.
    */
   public final void setHtmlSafe(boolean htmlSafe) {
     this.htmlSafe = htmlSafe;
   }
 
   /**
-   * Returns true if this writer writes JSON that's safe for inclusion in HTML
-   * and XML documents.
+   * Returns true if this writer writes JSON that's safe for inclusion in HTML and XML documents.
    */
   public final boolean isHtmlSafe() {
     return htmlSafe;
   }
 
   /**
-   * Sets whether object members are serialized when their value is null.
-   * This has no impact on array elements. The default is true.
+   * Sets whether object members are serialized when their value is null. This has no impact on
+   * array elements. The default is true.
    */
   public final void setSerializeNulls(boolean serializeNulls) {
     this.serializeNulls = serializeNulls;
   }
 
   /**
-   * Returns true if object members are serialized when their value is null.
-   * This has no impact on array elements. The default is true.
+   * Returns true if object members are serialized when their value is null. This has no impact on
+   * array elements. The default is true.
    */
   public final boolean getSerializeNulls() {
     return serializeNulls;
@@ -398,25 +374,29 @@ public class JsonWriter implements Closeable, Flushable {
 
   /**
    * Sets whether serialized entry names may omit quotes (like in json5)
-   * The default is false
+   * The default is false.
    */
   public final void setOmitQuotes(boolean omitQuotes) {
     this.omitQuotes = omitQuotes;
   }
 
+  /**
+   * Returns true serialized entry names may omit quotes (like in json5)
+   * The default is false.
+   */
   public final boolean getOmitQuotes() {
     return omitQuotes;
   }
 
   /**
-   * Begins encoding a new array. Each call to this method must be paired with
-   * a call to {@link #endArray}.
+   * Begins encoding a new array. Each call to this method must be paired with a call to {@link
+   * #endArray}.
    *
    * @return this writer.
    */
   public JsonWriter beginArray() throws IOException {
     writeDeferredName();
-    return open(EMPTY_ARRAY, '[');
+    return openScope(EMPTY_ARRAY, '[');
   }
 
   /**
@@ -425,18 +405,18 @@ public class JsonWriter implements Closeable, Flushable {
    * @return this writer.
    */
   public JsonWriter endArray() throws IOException {
-    return close(EMPTY_ARRAY, NONEMPTY_ARRAY, ']');
+    return closeScope(EMPTY_ARRAY, NONEMPTY_ARRAY, ']');
   }
 
   /**
-   * Begins encoding a new object. Each call to this method must be paired
-   * with a call to {@link #endObject}.
+   * Begins encoding a new object. Each call to this method must be paired with a call to {@link
+   * #endObject}.
    *
    * @return this writer.
    */
   public JsonWriter beginObject() throws IOException {
     writeDeferredName();
-    return open(EMPTY_OBJECT, '{');
+    return openScope(EMPTY_OBJECT, '{');
   }
 
   /**
@@ -445,26 +425,19 @@ public class JsonWriter implements Closeable, Flushable {
    * @return this writer.
    */
   public JsonWriter endObject() throws IOException {
-    return close(EMPTY_OBJECT, NONEMPTY_OBJECT, '}');
+    return closeScope(EMPTY_OBJECT, NONEMPTY_OBJECT, '}');
   }
 
-  /**
-   * Enters a new scope by appending any necessary whitespace and the given
-   * bracket.
-   */
-  private JsonWriter open(int empty, char openBracket) throws IOException {
+  /** Enters a new scope by appending any necessary whitespace and the given bracket. */
+  private JsonWriter openScope(int empty, char openBracket) throws IOException {
     beforeValue();
     push(empty);
     out.write(openBracket);
     return this;
   }
 
-  /**
-   * Closes the current scope by appending any necessary whitespace and the
-   * given bracket.
-   */
-  private JsonWriter close(int empty, int nonempty, char closeBracket)
-      throws IOException {
+  /** Closes the current scope by appending any necessary whitespace and the given bracket. */
+  private JsonWriter closeScope(int empty, int nonempty, char closeBracket) throws IOException {
     int context = peek();
     if (context != nonempty && context != empty) {
       throw new IllegalStateException("Nesting problem.");
@@ -494,9 +467,7 @@ public class JsonWriter implements Closeable, Flushable {
     stack[stackSize++] = newTop;
   }
 
-  /**
-   * Returns the value on the top of the stack.
-   */
+  /** Returns the value on the top of the stack. */
   private int peek() {
     if (stackSize == 0) {
       throw new IllegalStateException("JsonWriter is closed.");
@@ -504,9 +475,7 @@ public class JsonWriter implements Closeable, Flushable {
     return stack[stackSize - 1];
   }
 
-  /**
-   * Replace the value on the top of the stack with the given value.
-   */
+  /** Replace the value on the top of the stack with the given value. */
   private void replaceTop(int topOfStack) {
     stack[stackSize - 1] = topOfStack;
   }
@@ -514,7 +483,7 @@ public class JsonWriter implements Closeable, Flushable {
   /**
    * Insert a comment at the current location.
    * May create a new line.
-   * This writer MUST be lenient to use this
+   * This writer MUST be lenient to use this.
    */
   public JsonWriter comment(String comment) throws IOException {
     if (strictness != Strictness.LENIENT) throw new MalformedJsonException("Cannot write comment in non-lenient JsonWriter.");
@@ -592,46 +561,6 @@ public class JsonWriter implements Closeable, Flushable {
     return this;
   }
 
-  /**
-   * Writes {@code value} directly to the writer without quoting or
-   * escaping. This might not be supported by all implementations, if
-   * not supported an {@code UnsupportedOperationException} is thrown.
-   *
-   * @param value the literal string value, or null to encode a null literal.
-   * @return this writer.
-   * @throws UnsupportedOperationException if this writer does not support
-   *    writing raw JSON values.
-   * @since 2.4
-   */
-  public JsonWriter jsonValue(String value) throws IOException {
-    if (value == null) {
-      return nullValue();
-    }
-    writeDeferredName();
-    beforeValue();
-    out.append(value);
-    return this;
-  }
-
-  /**
-   * Encodes {@code null}.
-   *
-   * @return this writer.
-   */
-  public JsonWriter nullValue() throws IOException {
-    if (deferredName != null) {
-      if (serializeNulls) {
-        writeDeferredName();
-      } else {
-        deferredName = null;
-        return this; // skip the name and the value
-      }
-    }
-    beforeValue();
-    out.write("null");
-    return this;
-  }
-
   /**
    * Encodes {@code value}.
    *
@@ -663,9 +592,8 @@ public class JsonWriter implements Closeable, Flushable {
   /**
    * Encodes {@code value}.
    *
-   * @param value a finite value, or if {@link #setStrictness(Strictness) lenient},
-   *     also {@link Float#isNaN() NaN} or {@link Float#isInfinite()
-   *     infinity}.
+   * @param value a finite value, or if {@link #setStrictness(Strictness) lenient}, also {@link
+   *     Float#isNaN() NaN} or {@link Float#isInfinite() infinity}.
    * @return this writer.
    * @throws IllegalArgumentException if the value is NaN or Infinity and this writer is not {@link
    *     #setStrictness(Strictness) lenient}.
@@ -684,11 +612,11 @@ public class JsonWriter implements Closeable, Flushable {
   /**
    * Encodes {@code value}.
    *
-   * @param value a finite value, or if {@link #setStrictness(Strictness) lenient},
-   *     also {@link Double#isNaN() NaN} or {@link Double#isInfinite() infinity}.
+   * @param value a finite value, or if {@link #setStrictness(Strictness) lenient}, also {@link
+   *     Double#isNaN() NaN} or {@link Double#isInfinite() infinity}.
    * @return this writer.
-   * @throws IllegalArgumentException if the value is NaN or Infinity and this writer is
-   *     not {@link #setStrictness(Strictness) lenient}.
+   * @throws IllegalArgumentException if the value is NaN or Infinity and this writer is not {@link
+   *     #setStrictness(Strictness) lenient}.
    */
   public JsonWriter value(double value) throws IOException {
     writeDeferredName();
@@ -712,27 +640,16 @@ public class JsonWriter implements Closeable, Flushable {
     return this;
   }
 
-  /**
-   * Returns whether the {@code toString()} of {@code c} can be trusted to return
-   * a valid JSON number.
-   */
-  private static boolean isTrustedNumberType(Class<? extends Number> c) {
-    // Note: Don't consider LazilyParsedNumber trusted because it could contain
-    // an arbitrary malformed string
-    return c == Integer.class || c == Long.class || c == Double.class || c == Float.class || c == Byte.class || c == Short.class
-        || c == BigDecimal.class || c == BigInteger.class || c == AtomicInteger.class || c == AtomicLong.class;
-  }
-
   /**
    * Encodes {@code value}. The value is written by directly writing the {@link Number#toString()}
    * result to JSON. Implementations must make sure that the result represents a valid JSON number.
    *
-   * @param value a finite value, or if {@link #setStrictness(Strictness) lenient},
-   *     also {@link Double#isNaN() NaN} or {@link Double#isInfinite() infinity}.
+   * @param value a finite value, or if {@link #setStrictness(Strictness) lenient}, also {@link
+   *     Double#isNaN() NaN} or {@link Double#isInfinite() infinity}.
    * @return this writer.
-   * @throws IllegalArgumentException if the value is NaN or Infinity and this writer is
-   *     not {@link #setStrictness(Strictness) lenient}; or if the {@code toString()} result is not a
-   *     valid JSON number.
+   * @throws IllegalArgumentException if the value is NaN or Infinity and this writer is not {@link
+   *     #setStrictness(Strictness) lenient}; or if the {@code toString()} result is not a valid
+   *     JSON number.
    */
   public JsonWriter value(Number value) throws IOException {
     if (value == null) {
@@ -748,8 +665,10 @@ public class JsonWriter implements Closeable, Flushable {
     } else {
       Class<? extends Number> numberClass = value.getClass();
       // Validate that string is valid before writing it directly to JSON output
-      if (!isTrustedNumberType(numberClass) && !VALID_JSON_NUMBER_PATTERN.matcher(string).matches()) {
-        throw new IllegalArgumentException("String created by " + numberClass + " is not a valid JSON number: " + string);
+      if (!isTrustedNumberType(numberClass)
+          && !VALID_JSON_NUMBER_PATTERN.matcher(string).matches()) {
+        throw new IllegalArgumentException(
+            "String created by " + numberClass + " is not a valid JSON number: " + string);
       }
     }
 
@@ -759,10 +678,49 @@ public class JsonWriter implements Closeable, Flushable {
   }
 
   /**
-   * Ensures all buffered data is written to the underlying {@link Writer}
-   * and flushes that writer.
+   * Encodes {@code null}.
+   *
+   * @return this writer.
    */
-  @Override public void flush() throws IOException {
+  public JsonWriter nullValue() throws IOException {
+    if (deferredName != null) {
+      if (serializeNulls) {
+        writeDeferredName();
+      } else {
+        deferredName = null;
+        return this; // skip the name and the value
+      }
+    }
+    beforeValue();
+    out.write("null");
+    return this;
+  }
+
+  /**
+   * Writes {@code value} directly to the writer without quoting or escaping. This might not be
+   * supported by all implementations, if not supported an {@code UnsupportedOperationException} is
+   * thrown.
+   *
+   * @param value the literal string value, or null to encode a null literal.
+   * @return this writer.
+   * @throws UnsupportedOperationException if this writer does not support writing raw JSON values.
+   * @since 2.4
+   */
+  public JsonWriter jsonValue(String value) throws IOException {
+    if (value == null) {
+      return nullValue();
+    }
+    writeDeferredName();
+    beforeValue();
+    out.append(value);
+    return this;
+  }
+
+  /**
+   * Ensures all buffered data is written to the underlying {@link Writer} and flushes that writer.
+   */
+  @Override
+  public void flush() throws IOException {
     if (stackSize == 0) {
       throw new IllegalStateException("JsonWriter is closed.");
     }
@@ -774,7 +732,8 @@ public class JsonWriter implements Closeable, Flushable {
    *
    * @throws IOException if the JSON document is incomplete.
    */
-  @Override public void close() throws IOException {
+  @Override
+  public void close() throws IOException {
     out.close();
 
     int size = stackSize;
@@ -784,24 +743,33 @@ public class JsonWriter implements Closeable, Flushable {
     stackSize = 0;
   }
 
+  /**
+   * Returns whether the {@code toString()} of {@code c} can be trusted to return a valid JSON
+   * number.
+   */
+  private static boolean isTrustedNumberType(Class<? extends Number> c) {
+    // Note: Don't consider LazilyParsedNumber trusted because it could contain
+    // an arbitrary malformed string
+    return c == Integer.class
+        || c == Long.class
+        || c == Double.class
+        || c == Float.class
+        || c == Byte.class
+        || c == Short.class
+        || c == BigDecimal.class
+        || c == BigInteger.class
+        || c == AtomicInteger.class
+        || c == AtomicLong.class;
+  }
+
   private void string(String value) throws IOException {
-    String[] replacements = htmlSafe ? HTML_SAFE_REPLACEMENT_CHARS : REPLACEMENT_CHARS;
     out.write('\"');
     int last = 0;
     int length = value.length();
     for (int i = 0; i < length; i++) {
       char c = value.charAt(i);
-      String replacement;
-      if (c < 128) {
-        replacement = replacements[c];
-        if (replacement == null) {
-          continue;
-        }
-      } else if (c == '\u2028') {
-        replacement = "\\u2028";
-      } else if (c == '\u2029') {
-        replacement = "\\u2029";
-      } else {
+      String replacement = htmlSafe ? StringEscapeUtil.getHtmlSafeReplacement(c) : StringEscapeUtil.getReplacement(c);
+      if (replacement == null) {
         continue;
       }
       if (last < i) {
@@ -828,8 +796,8 @@ public class JsonWriter implements Closeable, Flushable {
   }
 
   /**
-   * Inserts any necessary separators and whitespace before a name. Also
-   * adjusts the stack to expect the name's value.
+   * Inserts any necessary separators and whitespace before a name. Also adjusts the stack to expect
+   * the name's value.
    */
   private void beforeName() throws IOException {
     int context = peek();
@@ -847,56 +815,55 @@ public class JsonWriter implements Closeable, Flushable {
   }
 
   /**
-   * Inserts any necessary separators and whitespace before a literal value,
-   * inline array, or inline object. Also adjusts the stack to expect either a
-   * closing bracket or another element.
+   * Inserts any necessary separators and whitespace before a literal value, inline array, or inline
+   * object. Also adjusts the stack to expect either a closing bracket or another element.
    */
   @SuppressWarnings("fallthrough")
   private void beforeValue() throws IOException {
     switch (peek()) {
-    case NONEMPTY_DOCUMENT:
-      if (strictness != Strictness.LENIENT) {
-        throw new IllegalStateException("JSON must have only one top-level value.");
-      }
-      // fall-through
-    case EMPTY_DOCUMENT: // first in document
-      replaceTop(NONEMPTY_DOCUMENT);
-      if (!deferredComment.isEmpty()) {
-        writeDeferredComment();
-        newline();
-      }
-      break;
+      case NONEMPTY_DOCUMENT:
+        if (strictness != Strictness.LENIENT) {
+          throw new IllegalStateException("JSON must have only one top-level value.");
+        }
+        // fall-through
+      case EMPTY_DOCUMENT: // first in document
+        replaceTop(NONEMPTY_DOCUMENT);
+        if (!deferredComment.isEmpty()) {
+          writeDeferredComment();
+          newline();
+        }
+        break;
 
-    case EMPTY_ARRAY: // first in array
-      replaceTop(NONEMPTY_ARRAY);
-      newline();
-      if (!deferredComment.isEmpty()) {
-        writeDeferredComment();
+      case EMPTY_ARRAY: // first in array
+        replaceTop(NONEMPTY_ARRAY);
         newline();
-      }
-      break;
+        if (!deferredComment.isEmpty()) {
+          writeDeferredComment();
+          newline();
+        }
+        break;
 
-    case NONEMPTY_ARRAY: // another in array
-      out.append(formattedComma);
-      newline();
-      if (!deferredComment.isEmpty()) {
-        writeDeferredComment();
+      case NONEMPTY_ARRAY: // another in array
+        out.append(formattedComma);
         newline();
-      }
-      break;
+        if (!deferredComment.isEmpty()) {
+          writeDeferredComment();
+          newline();
+        }
+        break;
 
-    case DANGLING_NAME: // value for name
-      out.append(formattedColon);
-      if (!deferredComment.isEmpty()) {
-        newline();
-        writeDeferredComment();
-        newline();
-      }
-      replaceTop(NONEMPTY_OBJECT);
-      break;
+      case DANGLING_NAME: // value for name
+        out.append(formattedColon);
+        if (!deferredComment.isEmpty()) {
+          newline();
+          writeDeferredComment();
+          newline();
+        }
+        replaceTop(NONEMPTY_OBJECT);
+        break;
 
-    default:
-      throw new IllegalStateException("Nesting problem.");
+      default:
+        throw new IllegalStateException("Nesting problem.");
     }
   }
 }

gson/src/main/java/com/google/gson/stream/MalformedJsonException.java

@@ -20,8 +20,8 @@ import com.google.gson.Strictness;
 import java.io.IOException;
 
 /**
- * Thrown when a reader encounters malformed JSON. Some syntax errors can be
- * ignored by using {@link Strictness#LENIENT} for {@link JsonReader#setStrictness(Strictness)}.
+ * Thrown when a reader encounters malformed JSON. Some syntax errors can be ignored by using {@link
+ * Strictness#LENIENT} for {@link JsonReader#setStrictness(Strictness)}.
  */
 public final class MalformedJsonException extends IOException {
   private static final long serialVersionUID = 1L;

gson/src/main/java/com/google/gson/stream/package-info.java

@@ -14,7 +14,5 @@
  * limitations under the License.
  */
 
-/**
- * This package provides classes for processing JSON in an efficient streaming way.
- */
+/** This package provides classes for processing JSON in an efficient streaming way. */
 package com.google.gson.stream;

gson/src/main/java/com/google/gson/util/ISO8601Utils.java

@@ -25,349 +25,361 @@ import java.util.Locale;
 import java.util.TimeZone;
 
 /**
- * Utilities methods for manipulating dates in iso8601 format. This is much faster and GC friendly than using SimpleDateFormat so
- * highly suitable if you (un)serialize lots of date objects.
- * 
- * Supported parse format: [yyyy-MM-dd|yyyyMMdd][T(hh:mm[:ss[.sss]]|hhmm[ss[.sss]])]?[Z|[+-]hh[:]mm]]
- * 
+ * Utilities methods for manipulating dates in iso8601 format. This is much faster and GC friendly
+ * than using SimpleDateFormat so highly suitable if you (un)serialize lots of date objects.
+ *
+ * <p>Supported parse format:
+ * [yyyy-MM-dd|yyyyMMdd][T(hh:mm[:ss[.sss]]|hhmm[ss[.sss]])]?[Z|[+-]hh[:]mm]]
+ *
  * @see <a href="http://www.w3.org/TR/NOTE-datetime">this specification</a>
  */
 // Date parsing code from Jackson databind ISO8601Utils.java
 // https://github.com/FasterXML/jackson-databind/blob/2.8/src/main/java/com/fasterxml/jackson/databind/util/ISO8601Utils.java
-public class ISO8601Utils
-{
-    /**
-     * ID to represent the 'UTC' string, default timezone since Jackson 2.7
-     * 
-     * @since 2.7
-     */
-    private static final String UTC_ID = "UTC";
-    /**
-     * The UTC timezone, prefetched to avoid more lookups.
-     * 
-     * @since 2.7
-     */
-    private static final TimeZone TIMEZONE_UTC = TimeZone.getTimeZone(UTC_ID);
+public class ISO8601Utils {
+  private ISO8601Utils() {}
 
-    /*
-    /**********************************************************
-    /* Formatting
-    /**********************************************************
-     */
+  /**
+   * ID to represent the 'UTC' string, default timezone since Jackson 2.7
+   *
+   * @since 2.7
+   */
+  private static final String UTC_ID = "UTC";
 
-    /**
-     * Format a date into 'yyyy-MM-ddThh:mm:ssZ' (default timezone, no milliseconds precision)
-     * 
-     * @param date the date to format
-     * @return the date formatted as 'yyyy-MM-ddThh:mm:ssZ'
-     */
-    public static String format(Date date) {
-        return format(date, false, TIMEZONE_UTC);
+  /**
+   * The UTC timezone, prefetched to avoid more lookups.
+   *
+   * @since 2.7
+   */
+  private static final TimeZone TIMEZONE_UTC = TimeZone.getTimeZone(UTC_ID);
+
+  /*
+  /**********************************************************
+  /* Formatting
+  /**********************************************************
+   */
+
+  /**
+   * Format a date into 'yyyy-MM-ddThh:mm:ssZ' (default timezone, no milliseconds precision)
+   *
+   * @param date the date to format
+   * @return the date formatted as 'yyyy-MM-ddThh:mm:ssZ'
+   */
+  public static String format(Date date) {
+    return format(date, false, TIMEZONE_UTC);
+  }
+
+  /**
+   * Format a date into 'yyyy-MM-ddThh:mm:ss[.sss]Z' (GMT timezone)
+   *
+   * @param date the date to format
+   * @param millis true to include millis precision otherwise false
+   * @return the date formatted as 'yyyy-MM-ddThh:mm:ss[.sss]Z'
+   */
+  public static String format(Date date, boolean millis) {
+    return format(date, millis, TIMEZONE_UTC);
+  }
+
+  /**
+   * Format date into yyyy-MM-ddThh:mm:ss[.sss][Z|[+-]hh:mm]
+   *
+   * @param date the date to format
+   * @param millis true to include millis precision otherwise false
+   * @param tz timezone to use for the formatting (UTC will produce 'Z')
+   * @return the date formatted as yyyy-MM-ddThh:mm:ss[.sss][Z|[+-]hh:mm]
+   */
+  public static String format(Date date, boolean millis, TimeZone tz) {
+    Calendar calendar = new GregorianCalendar(tz, Locale.US);
+    calendar.setTime(date);
+
+    // estimate capacity of buffer as close as we can (yeah, that's pedantic ;)
+    int capacity = "yyyy-MM-ddThh:mm:ss".length();
+    capacity += millis ? ".sss".length() : 0;
+    capacity += tz.getRawOffset() == 0 ? "Z".length() : "+hh:mm".length();
+    StringBuilder formatted = new StringBuilder(capacity);
+
+    padInt(formatted, calendar.get(Calendar.YEAR), "yyyy".length());
+    formatted.append('-');
+    padInt(formatted, calendar.get(Calendar.MONTH) + 1, "MM".length());
+    formatted.append('-');
+    padInt(formatted, calendar.get(Calendar.DAY_OF_MONTH), "dd".length());
+    formatted.append('T');
+    padInt(formatted, calendar.get(Calendar.HOUR_OF_DAY), "hh".length());
+    formatted.append(':');
+    padInt(formatted, calendar.get(Calendar.MINUTE), "mm".length());
+    formatted.append(':');
+    padInt(formatted, calendar.get(Calendar.SECOND), "ss".length());
+    if (millis) {
+      formatted.append('.');
+      padInt(formatted, calendar.get(Calendar.MILLISECOND), "sss".length());
     }
 
-    /**
-     * Format a date into 'yyyy-MM-ddThh:mm:ss[.sss]Z' (GMT timezone)
-     * 
-     * @param date the date to format
-     * @param millis true to include millis precision otherwise false
-     * @return the date formatted as 'yyyy-MM-ddThh:mm:ss[.sss]Z'
-     */
-    public static String format(Date date, boolean millis) {
-        return format(date, millis, TIMEZONE_UTC);
+    int offset = tz.getOffset(calendar.getTimeInMillis());
+    if (offset != 0) {
+      int hours = Math.abs((offset / (60 * 1000)) / 60);
+      int minutes = Math.abs((offset / (60 * 1000)) % 60);
+      formatted.append(offset < 0 ? '-' : '+');
+      padInt(formatted, hours, "hh".length());
+      formatted.append(':');
+      padInt(formatted, minutes, "mm".length());
+    } else {
+      formatted.append('Z');
     }
 
-    /**
-     * Format date into yyyy-MM-ddThh:mm:ss[.sss][Z|[+-]hh:mm]
-     * 
-     * @param date the date to format
-     * @param millis true to include millis precision otherwise false
-     * @param tz timezone to use for the formatting (UTC will produce 'Z')
-     * @return the date formatted as yyyy-MM-ddThh:mm:ss[.sss][Z|[+-]hh:mm]
-     */
-    public static String format(Date date, boolean millis, TimeZone tz) {
-        Calendar calendar = new GregorianCalendar(tz, Locale.US);
-        calendar.setTime(date);
+    return formatted.toString();
+  }
 
-        // estimate capacity of buffer as close as we can (yeah, that's pedantic ;)
-        int capacity = "yyyy-MM-ddThh:mm:ss".length();
-        capacity += millis ? ".sss".length() : 0;
-        capacity += tz.getRawOffset() == 0 ? "Z".length() : "+hh:mm".length();
-        StringBuilder formatted = new StringBuilder(capacity);
+  /*
+  /**********************************************************
+  /* Parsing
+  /**********************************************************
+   */
 
-        padInt(formatted, calendar.get(Calendar.YEAR), "yyyy".length());
-        formatted.append('-');
-        padInt(formatted, calendar.get(Calendar.MONTH) + 1, "MM".length());
-        formatted.append('-');
-        padInt(formatted, calendar.get(Calendar.DAY_OF_MONTH), "dd".length());
-        formatted.append('T');
-        padInt(formatted, calendar.get(Calendar.HOUR_OF_DAY), "hh".length());
-        formatted.append(':');
-        padInt(formatted, calendar.get(Calendar.MINUTE), "mm".length());
-        formatted.append(':');
-        padInt(formatted, calendar.get(Calendar.SECOND), "ss".length());
-        if (millis) {
-            formatted.append('.');
-            padInt(formatted, calendar.get(Calendar.MILLISECOND), "sss".length());
+  /**
+   * Parse a date from ISO-8601 formatted string. It expects a format
+   * [yyyy-MM-dd|yyyyMMdd][T(hh:mm[:ss[.sss]]|hhmm[ss[.sss]])]?[Z|[+-]hh[:mm]]]
+   *
+   * @param date ISO string to parse in the appropriate format.
+   * @param pos The position to start parsing from, updated to where parsing stopped.
+   * @return the parsed date
+   * @throws ParseException if the date is not in the appropriate format
+   */
+  public static Date parse(String date, ParsePosition pos) throws ParseException {
+    Exception fail = null;
+    try {
+      int offset = pos.getIndex();
+
+      // extract year
+      int year = parseInt(date, offset, offset += 4);
+      if (checkOffset(date, offset, '-')) {
+        offset += 1;
+      }
+
+      // extract month
+      int month = parseInt(date, offset, offset += 2);
+      if (checkOffset(date, offset, '-')) {
+        offset += 1;
+      }
+
+      // extract day
+      int day = parseInt(date, offset, offset += 2);
+
+      // default time value
+      int hour = 0;
+      int minutes = 0;
+      int seconds = 0;
+
+      // always use 0 otherwise returned date will include millis of current time
+      int milliseconds = 0;
+
+      // if the value has no time component (and no time zone), we are done
+      boolean hasT = checkOffset(date, offset, 'T');
+
+      if (!hasT && (date.length() <= offset)) {
+        Calendar calendar = new GregorianCalendar(year, month - 1, day);
+        calendar.setLenient(false);
+
+        pos.setIndex(offset);
+        return calendar.getTime();
+      }
+
+      if (hasT) {
+
+        // extract hours, minutes, seconds and milliseconds
+        hour = parseInt(date, offset += 1, offset += 2);
+        if (checkOffset(date, offset, ':')) {
+          offset += 1;
         }
 
-        int offset = tz.getOffset(calendar.getTimeInMillis());
-        if (offset != 0) {
-            int hours = Math.abs((offset / (60 * 1000)) / 60);
-            int minutes = Math.abs((offset / (60 * 1000)) % 60);
-            formatted.append(offset < 0 ? '-' : '+');
-            padInt(formatted, hours, "hh".length());
-            formatted.append(':');
-            padInt(formatted, minutes, "mm".length());
+        minutes = parseInt(date, offset, offset += 2);
+        if (checkOffset(date, offset, ':')) {
+          offset += 1;
+        }
+        // second and milliseconds can be optional
+        if (date.length() > offset) {
+          char c = date.charAt(offset);
+          if (c != 'Z' && c != '+' && c != '-') {
+            seconds = parseInt(date, offset, offset += 2);
+            if (seconds > 59 && seconds < 63) {
+              seconds = 59; // truncate up to 3 leap seconds
+            }
+            // milliseconds can be optional in the format
+            if (checkOffset(date, offset, '.')) {
+              offset += 1;
+              int endOffset = indexOfNonDigit(date, offset + 1); // assume at least one digit
+              int parseEndOffset = Math.min(endOffset, offset + 3); // parse up to 3 digits
+              int fraction = parseInt(date, offset, parseEndOffset);
+              // compensate for "missing" digits
+              switch (parseEndOffset - offset) { // number of digits parsed
+                case 2:
+                  milliseconds = fraction * 10;
+                  break;
+                case 1:
+                  milliseconds = fraction * 100;
+                  break;
+                default:
+                  milliseconds = fraction;
+              }
+              offset = endOffset;
+            }
+          }
+        }
+      }
+
+      // extract timezone
+      if (date.length() <= offset) {
+        throw new IllegalArgumentException("No time zone indicator");
+      }
+
+      TimeZone timezone = null;
+      char timezoneIndicator = date.charAt(offset);
+
+      if (timezoneIndicator == 'Z') {
+        timezone = TIMEZONE_UTC;
+        offset += 1;
+      } else if (timezoneIndicator == '+' || timezoneIndicator == '-') {
+        String timezoneOffset = date.substring(offset);
+
+        // When timezone has no minutes, we should append it, valid timezones are, for example:
+        // +00:00, +0000 and +00
+        timezoneOffset = timezoneOffset.length() >= 5 ? timezoneOffset : timezoneOffset + "00";
+
+        offset += timezoneOffset.length();
+        // 18-Jun-2015, tatu: Minor simplification, skip offset of "+0000"/"+00:00"
+        if (timezoneOffset.equals("+0000") || timezoneOffset.equals("+00:00")) {
+          timezone = TIMEZONE_UTC;
         } else {
-            formatted.append('Z');
-        }
+          // 18-Jun-2015, tatu: Looks like offsets only work from GMT, not UTC...
+          //    not sure why, but that's the way it looks. Further, Javadocs for
+          //    `java.util.TimeZone` specifically instruct use of GMT as base for
+          //    custom timezones... odd.
+          String timezoneId = "GMT" + timezoneOffset;
+          // String timezoneId = "UTC" + timezoneOffset;
 
-        return formatted.toString();
+          timezone = TimeZone.getTimeZone(timezoneId);
+
+          String act = timezone.getID();
+          if (!act.equals(timezoneId)) {
+            /* 22-Jan-2015, tatu: Looks like canonical version has colons, but we may be given
+             *    one without. If so, don't sweat.
+             *   Yes, very inefficient. Hopefully not hit often.
+             *   If it becomes a perf problem, add 'loose' comparison instead.
+             */
+            String cleaned = act.replace(":", "");
+            if (!cleaned.equals(timezoneId)) {
+              throw new IndexOutOfBoundsException(
+                  "Mismatching time zone indicator: "
+                      + timezoneId
+                      + " given, resolves to "
+                      + timezone.getID());
+            }
+          }
+        }
+      } else {
+        throw new IndexOutOfBoundsException(
+            "Invalid time zone indicator '" + timezoneIndicator + "'");
+      }
+
+      Calendar calendar = new GregorianCalendar(timezone);
+      calendar.setLenient(false);
+      calendar.set(Calendar.YEAR, year);
+      calendar.set(Calendar.MONTH, month - 1);
+      calendar.set(Calendar.DAY_OF_MONTH, day);
+      calendar.set(Calendar.HOUR_OF_DAY, hour);
+      calendar.set(Calendar.MINUTE, minutes);
+      calendar.set(Calendar.SECOND, seconds);
+      calendar.set(Calendar.MILLISECOND, milliseconds);
+
+      pos.setIndex(offset);
+      return calendar.getTime();
+      // If we get a ParseException it'll already have the right message/offset.
+      // Other exception types can convert here.
+    } catch (IndexOutOfBoundsException | IllegalArgumentException e) {
+      fail = e;
     }
-
-    /*
-    /**********************************************************
-    /* Parsing
-    /**********************************************************
-     */
-
-    /**
-     * Parse a date from ISO-8601 formatted string. It expects a format
-     * [yyyy-MM-dd|yyyyMMdd][T(hh:mm[:ss[.sss]]|hhmm[ss[.sss]])]?[Z|[+-]hh[:mm]]]
-     * 
-     * @param date ISO string to parse in the appropriate format.
-     * @param pos The position to start parsing from, updated to where parsing stopped.
-     * @return the parsed date
-     * @throws ParseException if the date is not in the appropriate format
-     */
-    public static Date parse(String date, ParsePosition pos) throws ParseException {
-        Exception fail = null;
-        try {
-            int offset = pos.getIndex();
-
-            // extract year
-            int year = parseInt(date, offset, offset += 4);
-            if (checkOffset(date, offset, '-')) {
-                offset += 1;
-            }
-
-            // extract month
-            int month = parseInt(date, offset, offset += 2);
-            if (checkOffset(date, offset, '-')) {
-                offset += 1;
-            }
-
-            // extract day
-            int day = parseInt(date, offset, offset += 2);
-            // default time value
-            int hour = 0;
-            int minutes = 0;
-            int seconds = 0;
-            int milliseconds = 0; // always use 0 otherwise returned date will include millis of current time
-
-            // if the value has no time component (and no time zone), we are done
-            boolean hasT = checkOffset(date, offset, 'T');
-
-            if (!hasT && (date.length() <= offset)) {
-                Calendar calendar = new GregorianCalendar(year, month - 1, day);
-                calendar.setLenient(false);
-
-                pos.setIndex(offset);
-                return calendar.getTime();
-            }
-
-            if (hasT) {
-
-                // extract hours, minutes, seconds and milliseconds
-                hour = parseInt(date, offset += 1, offset += 2);
-                if (checkOffset(date, offset, ':')) {
-                    offset += 1;
-                }
-
-                minutes = parseInt(date, offset, offset += 2);
-                if (checkOffset(date, offset, ':')) {
-                    offset += 1;
-                }
-                // second and milliseconds can be optional
-                if (date.length() > offset) {
-                    char c = date.charAt(offset);
-                    if (c != 'Z' && c != '+' && c != '-') {
-                        seconds = parseInt(date, offset, offset += 2);
-                        if (seconds > 59 && seconds < 63) seconds = 59; // truncate up to 3 leap seconds
-                        // milliseconds can be optional in the format
-                        if (checkOffset(date, offset, '.')) {
-                            offset += 1;
-                            int endOffset = indexOfNonDigit(date, offset + 1); // assume at least one digit
-                            int parseEndOffset = Math.min(endOffset, offset + 3); // parse up to 3 digits
-                            int fraction = parseInt(date, offset, parseEndOffset);
-                            // compensate for "missing" digits
-                            switch (parseEndOffset - offset) { // number of digits parsed
-                            case 2:
-                                milliseconds = fraction * 10;
-                                break;
-                            case 1:
-                                milliseconds = fraction * 100;
-                                break;
-                            default:
-                                milliseconds = fraction;
-                            }
-                            offset = endOffset;
-                        }
-                    }
-                }
-            }
-
-            // extract timezone
-            if (date.length() <= offset) {
-                throw new IllegalArgumentException("No time zone indicator");
-            }
-
-            TimeZone timezone = null;
-            char timezoneIndicator = date.charAt(offset);
-
-            if (timezoneIndicator == 'Z') {
-                timezone = TIMEZONE_UTC;
-                offset += 1;
-            } else if (timezoneIndicator == '+' || timezoneIndicator == '-') {
-                String timezoneOffset = date.substring(offset);
-
-                // When timezone has no minutes, we should append it, valid timezones are, for example: +00:00, +0000 and +00
-                timezoneOffset = timezoneOffset.length() >= 5 ? timezoneOffset : timezoneOffset + "00";
-
-                offset += timezoneOffset.length();
-                // 18-Jun-2015, tatu: Minor simplification, skip offset of "+0000"/"+00:00"
-                if ("+0000".equals(timezoneOffset) || "+00:00".equals(timezoneOffset)) {
-                    timezone = TIMEZONE_UTC;
-                } else {
-                    // 18-Jun-2015, tatu: Looks like offsets only work from GMT, not UTC...
-                    //    not sure why, but that's the way it looks. Further, Javadocs for
-                    //    `java.util.TimeZone` specifically instruct use of GMT as base for
-                    //    custom timezones... odd.
-                    String timezoneId = "GMT" + timezoneOffset;
-//                    String timezoneId = "UTC" + timezoneOffset;
-
-                    timezone = TimeZone.getTimeZone(timezoneId);
-
-                    String act = timezone.getID();
-                    if (!act.equals(timezoneId)) {
-                        /* 22-Jan-2015, tatu: Looks like canonical version has colons, but we may be given
-                         *    one without. If so, don't sweat.
-                         *   Yes, very inefficient. Hopefully not hit often.
-                         *   If it becomes a perf problem, add 'loose' comparison instead.
-                         */
-                        String cleaned = act.replace(":", "");
-                        if (!cleaned.equals(timezoneId)) {
-                            throw new IndexOutOfBoundsException("Mismatching time zone indicator: "+timezoneId+" given, resolves to "
-                                    +timezone.getID());
-                        }
-                    }
-                }
-            } else {
-                throw new IndexOutOfBoundsException("Invalid time zone indicator '" + timezoneIndicator+"'");
-            }
-
-            Calendar calendar = new GregorianCalendar(timezone);
-            calendar.setLenient(false);
-            calendar.set(Calendar.YEAR, year);
-            calendar.set(Calendar.MONTH, month - 1);
-            calendar.set(Calendar.DAY_OF_MONTH, day);
-            calendar.set(Calendar.HOUR_OF_DAY, hour);
-            calendar.set(Calendar.MINUTE, minutes);
-            calendar.set(Calendar.SECOND, seconds);
-            calendar.set(Calendar.MILLISECOND, milliseconds);
-
-            pos.setIndex(offset);
-            return calendar.getTime();
-            // If we get a ParseException it'll already have the right message/offset.
-            // Other exception types can convert here.
-        } catch (IndexOutOfBoundsException e) {
-            fail = e;
-        } catch (NumberFormatException e) {
-            fail = e;
-        } catch (IllegalArgumentException e) {
-            fail = e;
-        }
-        String input = (date == null) ? null : ('"' + date + '"');
-        String msg = fail.getMessage();
-        if (msg == null || msg.isEmpty()) {
-            msg = "("+fail.getClass().getName()+")";
-        }
-        ParseException ex = new ParseException("Failed to parse date [" + input + "]: " + msg, pos.getIndex());
-        ex.initCause(fail);
-        throw ex;
+    String input = (date == null) ? null : ('"' + date + '"');
+    String msg = fail.getMessage();
+    if (msg == null || msg.isEmpty()) {
+      msg = "(" + fail.getClass().getName() + ")";
     }
+    ParseException ex =
+        new ParseException("Failed to parse date [" + input + "]: " + msg, pos.getIndex());
+    ex.initCause(fail);
+    throw ex;
+  }
 
-    /**
-     * Check if the expected character exist at the given offset in the value.
-     * 
-     * @param value the string to check at the specified offset
-     * @param offset the offset to look for the expected character
-     * @param expected the expected character
-     * @return true if the expected character exist at the given offset
-     */
-    private static boolean checkOffset(String value, int offset, char expected) {
-        return (offset < value.length()) && (value.charAt(offset) == expected);
+  /**
+   * Check if the expected character exist at the given offset in the value.
+   *
+   * @param value the string to check at the specified offset
+   * @param offset the offset to look for the expected character
+   * @param expected the expected character
+   * @return true if the expected character exist at the given offset
+   */
+  private static boolean checkOffset(String value, int offset, char expected) {
+    return (offset < value.length()) && (value.charAt(offset) == expected);
+  }
+
+  /**
+   * Parse an integer located between 2 given offsets in a string
+   *
+   * @param value the string to parse
+   * @param beginIndex the start index for the integer in the string
+   * @param endIndex the end index for the integer in the string
+   * @return the int
+   * @throws NumberFormatException if the value is not a number
+   */
+  private static int parseInt(String value, int beginIndex, int endIndex)
+      throws NumberFormatException {
+    if (beginIndex < 0 || endIndex > value.length() || beginIndex > endIndex) {
+      throw new NumberFormatException(value);
     }
-
-    /**
-     * Parse an integer located between 2 given offsets in a string
-     * 
-     * @param value the string to parse
-     * @param beginIndex the start index for the integer in the string
-     * @param endIndex the end index for the integer in the string
-     * @return the int
-     * @throws NumberFormatException if the value is not a number
-     */
-    private static int parseInt(String value, int beginIndex, int endIndex) throws NumberFormatException {
-        if (beginIndex < 0 || endIndex > value.length() || beginIndex > endIndex) {
-            throw new NumberFormatException(value);
-        }
-        // use same logic as in Integer.parseInt() but less generic we're not supporting negative values
-        int i = beginIndex;
-        int result = 0;
-        int digit;
-        if (i < endIndex) {
-            digit = Character.digit(value.charAt(i++), 10);
-            if (digit < 0) {
-                throw new NumberFormatException("Invalid number: " + value.substring(beginIndex, endIndex));
-            }
-            result = -digit;
-        }
-        while (i < endIndex) {
-            digit = Character.digit(value.charAt(i++), 10);
-            if (digit < 0) {
-                throw new NumberFormatException("Invalid number: " + value.substring(beginIndex, endIndex));
-            }
-            result *= 10;
-            result -= digit;
-        }
-        return -result;
+    // use same logic as in Integer.parseInt() but less generic we're not supporting negative values
+    int i = beginIndex;
+    int result = 0;
+    int digit;
+    if (i < endIndex) {
+      digit = Character.digit(value.charAt(i++), 10);
+      if (digit < 0) {
+        throw new NumberFormatException("Invalid number: " + value.substring(beginIndex, endIndex));
+      }
+      result = -digit;
     }
-
-    /**
-     * Zero pad a number to a specified length
-     * 
-     * @param buffer buffer to use for padding
-     * @param value the integer value to pad if necessary.
-     * @param length the length of the string we should zero pad
-     */
-    private static void padInt(StringBuilder buffer, int value, int length) {
-        String strValue = Integer.toString(value);
-        for (int i = length - strValue.length(); i > 0; i--) {
-            buffer.append('0');
-        }
-        buffer.append(strValue);
+    while (i < endIndex) {
+      digit = Character.digit(value.charAt(i++), 10);
+      if (digit < 0) {
+        throw new NumberFormatException("Invalid number: " + value.substring(beginIndex, endIndex));
+      }
+      result *= 10;
+      result -= digit;
     }
+    return -result;
+  }
 
-    /**
-     * Returns the index of the first character in the string that is not a digit, starting at offset.
-     */
-    private static int indexOfNonDigit(String string, int offset) {
-        for (int i = offset; i < string.length(); i++) {
-            char c = string.charAt(i);
-            if (c < '0' || c > '9') return i;
-        }
-        return string.length();
+  /**
+   * Zero pad a number to a specified length
+   *
+   * @param buffer buffer to use for padding
+   * @param value the integer value to pad if necessary.
+   * @param length the length of the string we should zero pad
+   */
+  private static void padInt(StringBuilder buffer, int value, int length) {
+    String strValue = Integer.toString(value);
+    for (int i = length - strValue.length(); i > 0; i--) {
+      buffer.append('0');
     }
+    buffer.append(strValue);
+  }
 
+  /**
+   * Returns the index of the first character in the string that is not a digit, starting at offset.
+   */
+  private static int indexOfNonDigit(String string, int offset) {
+    for (int i = offset; i < string.length(); i++) {
+      char c = string.charAt(i);
+      if (c < '0' || c > '9') {
+        return i;
+      }
+    }
+    return string.length();
+  }
 }

gson/src/main/java/com/google/gson/util/StringEscapeUtil.java

@@ -0,0 +1,80 @@
+package com.google.gson.util;
+
+/**
+ * Utilities methods for escaping strings, extracted from gsons JsonWriter.
+ * @author JFronny
+ */
+public class StringEscapeUtil {
+  private StringEscapeUtil() {}
+
+  /*
+   * From RFC 8259, "All Unicode characters may be placed within the
+   * quotation marks except for the characters that must be escaped:
+   * quotation mark, reverse solidus, and the control characters
+   * (U+0000 through U+001F)."
+   *
+   * We also escape '\u2028' and '\u2029', which JavaScript interprets as
+   * newline characters. This prevents eval() from failing with a syntax
+   * error. http://code.google.com/p/google-gson/issues/detail?id=341
+   */
+  private static final String[] REPLACEMENT_CHARS;
+  private static final String[] HTML_SAFE_REPLACEMENT_CHARS;
+
+  static {
+    REPLACEMENT_CHARS = new String[128];
+    for (int i = 0; i <= 0x1f; i++) {
+      REPLACEMENT_CHARS[i] = String.format("\\u%04x", i);
+    }
+    REPLACEMENT_CHARS['"'] = "\\\"";
+    REPLACEMENT_CHARS['\\'] = "\\\\";
+    REPLACEMENT_CHARS['\t'] = "\\t";
+    REPLACEMENT_CHARS['\b'] = "\\b";
+    REPLACEMENT_CHARS['\n'] = "\\n";
+    REPLACEMENT_CHARS['\r'] = "\\r";
+    REPLACEMENT_CHARS['\f'] = "\\f";
+    REPLACEMENT_CHARS['\0'] = "\\0";
+    HTML_SAFE_REPLACEMENT_CHARS = REPLACEMENT_CHARS.clone();
+    HTML_SAFE_REPLACEMENT_CHARS['<'] = "\\u003c";
+    HTML_SAFE_REPLACEMENT_CHARS['>'] = "\\u003e";
+    HTML_SAFE_REPLACEMENT_CHARS['&'] = "\\u0026";
+    HTML_SAFE_REPLACEMENT_CHARS['='] = "\\u003d";
+    HTML_SAFE_REPLACEMENT_CHARS['\''] = "\\u0027";
+  }
+
+  private static String getReplacement(char c, String[] replacements) {
+    String replacement;
+    if (c < 128) {
+      replacement = replacements[c];
+      if (replacement == null) {
+        return null;
+      }
+    } else if (c == '\u2028') {
+      replacement = "\\u2028";
+    } else if (c == '\u2029') {
+      replacement = "\\u2029";
+    } else {
+      return null;
+    }
+    return replacement;
+  }
+
+  /**
+   * Returns the replacement for the character, or null if the character does not need to be escaped.
+   * @param c the character to escape
+   * @return the replacement for the character, or null if the character does not need to be escaped
+   * @see #getHtmlSafeReplacement(char)
+   */
+  public static String getReplacement(char c) {
+    return getReplacement(c, REPLACEMENT_CHARS);
+  }
+
+  /**
+   * Returns the replacement for the character, or null if the character does not need to be escaped.
+   * @param c the character to escape
+   * @return the replacement for the character, or null if the character does not need to be escaped
+   * @see #getReplacement(char)
+   */
+  public static String getHtmlSafeReplacement(char c) {
+    return getReplacement(c, HTML_SAFE_REPLACEMENT_CHARS);
+  }
+}

gson/src/main/java/module-info.java

@@ -16,6 +16,7 @@
 
 /**
  * Defines the Gson serialization/deserialization API.
+ *
  * @since 2.8.6
  */
 module io.gitlab.jfronny.gson {

gson/src/test/java/com/google/gson/DefaultInetAddressTypeAdapterTest.java

@@ -24,17 +24,17 @@ import org.junit.Test;
 
 /**
  * Unit tests for the default serializer/deserializer for the {@code InetAddress} type.
- * 
+ *
  * @author Joel Leitch
  */
 public class DefaultInetAddressTypeAdapterTest {
   private Gson gson;
-  
+
   @Before
   public void setUp() throws Exception {
     gson = new Gson();
   }
-  
+
   @Test
   public void testInetAddressSerializationAndDeserialization() throws Exception {
     @SuppressWarnings("AddressSelection") // we really do want this method

gson/src/test/java/com/google/gson/DefaultMapJsonSerializerTest.java

@@ -25,8 +25,8 @@ import java.util.Map;
 import org.junit.Test;
 
 /**
- * Unit test for the default JSON map serialization object located in the
- * {@link DefaultTypeAdapters} class.
+ * Unit test for the default JSON map serialization object located in the {@link
+ * DefaultTypeAdapters} class.
  *
  * @author Joel Leitch
  */
@@ -44,7 +44,7 @@ public class DefaultMapJsonSerializerTest {
 
   @Test
   public void testEmptyMapSerialization() {
-    Type mapType = new TypeToken<Map<String, String>>() { }.getType();
+    Type mapType = new TypeToken<Map<String, String>>() {}.getType();
     Map<String, String> emptyMap = new HashMap<>();
     JsonElement element = gson.toJsonTree(emptyMap, mapType);
 
@@ -55,7 +55,7 @@ public class DefaultMapJsonSerializerTest {
 
   @Test
   public void testNonEmptyMapSerialization() {
-    Type mapType = new TypeToken<Map<String, String>>() { }.getType();
+    Type mapType = new TypeToken<Map<String, String>>() {}.getType();
     Map<String, String> myMap = new HashMap<>();
     String key = "key1";
     myMap.put(key, "value1");

gson/src/test/java/com/google/gson/ExposeAnnotationExclusionStrategyTest.java

@@ -31,38 +31,48 @@ import org.junit.Test;
 public class ExposeAnnotationExclusionStrategyTest {
   private Excluder excluder = Excluder.DEFAULT.excludeFieldsWithoutExposeAnnotation();
 
+  private void assertIncludesClass(Class<?> c) {
+    assertThat(excluder.excludeClass(c, true)).isFalse();
+    assertThat(excluder.excludeClass(c, false)).isFalse();
+  }
+
+  private void assertIncludesField(Field f) {
+    assertThat(excluder.excludeField(f, true)).isFalse();
+    assertThat(excluder.excludeField(f, false)).isFalse();
+  }
+
+  private void assertExcludesField(Field f) {
+    assertThat(excluder.excludeField(f, true)).isTrue();
+    assertThat(excluder.excludeField(f, false)).isTrue();
+  }
+
   @Test
   public void testNeverSkipClasses() {
-    assertThat(excluder.excludeClass(MockObject.class, true)).isFalse();
-    assertThat(excluder.excludeClass(MockObject.class, false)).isFalse();
+    assertIncludesClass(MockObject.class);
   }
 
   @Test
   public void testSkipNonAnnotatedFields() throws Exception {
     Field f = createFieldAttributes("hiddenField");
-    assertThat(excluder.excludeField(f, true)).isTrue();
-    assertThat(excluder.excludeField(f, false)).isTrue();
+    assertExcludesField(f);
   }
 
   @Test
   public void testSkipExplicitlySkippedFields() throws Exception {
     Field f = createFieldAttributes("explicitlyHiddenField");
-    assertThat(excluder.excludeField(f, true)).isTrue();
-    assertThat(excluder.excludeField(f, false)).isTrue();
+    assertExcludesField(f);
   }
 
   @Test
   public void testNeverSkipExposedAnnotatedFields() throws Exception {
     Field f = createFieldAttributes("exposedField");
-    assertThat(excluder.excludeField(f, true)).isFalse();
-    assertThat(excluder.excludeField(f, false)).isFalse();
+    assertIncludesField(f);
   }
 
   @Test
   public void testNeverSkipExplicitlyExposedAnnotatedFields() throws Exception {
     Field f = createFieldAttributes("explicitlyExposedField");
-    assertThat(excluder.excludeField(f, true)).isFalse();
-    assertThat(excluder.excludeField(f, false)).isFalse();
+    assertIncludesField(f);
   }
 
   @Test
@@ -78,16 +88,15 @@ public class ExposeAnnotationExclusionStrategyTest {
 
   @SuppressWarnings("unused")
   private static class MockObject {
-    @Expose
-    public final int exposedField = 0;
+    @Expose public final int exposedField = 0;
 
-    @Expose(serialize=true, deserialize=true)
+    @Expose(serialize = true, deserialize = true)
     public final int explicitlyExposedField = 0;
 
-    @Expose(serialize=false, deserialize=false)
+    @Expose(serialize = false, deserialize = false)
     public final int explicitlyHiddenField = 0;
 
-    @Expose(serialize=true, deserialize=false)
+    @Expose(serialize = true, deserialize = false)
     public final int explicitlyDifferentModeField = 0;
 
     public final int hiddenField = 0;

gson/src/test/java/com/google/gson/FieldAttributesTest.java

@@ -46,7 +46,8 @@ public class FieldAttributesTest {
     try {
       new FieldAttributes(null);
       fail("Field parameter can not be null");
-    } catch (NullPointerException expected) { }
+    } catch (NullPointerException expected) {
+    }
   }
 
   @Test

gson/src/test/java/com/google/gson/FieldNamingPolicyTest.java

@@ -19,29 +19,29 @@ package com.google.gson;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
 
+import com.google.gson.functional.FieldNamingTest;
 import java.lang.reflect.Field;
 import java.util.Locale;
 import org.junit.Test;
-import com.google.gson.functional.FieldNamingTest;
 
 /**
- * Performs tests directly against {@link FieldNamingPolicy}; for integration tests
- * see {@link FieldNamingTest}.
+ * Performs tests directly against {@link FieldNamingPolicy}; for integration tests see {@link
+ * FieldNamingTest}.
  */
 public class FieldNamingPolicyTest {
   @Test
   public void testSeparateCamelCase() {
     // Map from original -> expected
-    String[][] argumentPairs =  {
-      { "a", "a" },
-      { "ab", "ab" },
-      { "Ab", "Ab" },
-      { "aB", "a_B" },
-      { "AB", "A_B" },
-      { "A_B", "A__B" },
-      { "firstSecondThird", "first_Second_Third" },
-      { "__", "__" },
-      { "_123", "_123" }
+    String[][] argumentPairs = {
+      {"a", "a"},
+      {"ab", "ab"},
+      {"Ab", "Ab"},
+      {"aB", "a_B"},
+      {"AB", "A_B"},
+      {"A_B", "A__B"},
+      {"firstSecondThird", "first_Second_Third"},
+      {"__", "__"},
+      {"_123", "_123"}
     };
 
     for (String[] pair : argumentPairs) {
@@ -52,19 +52,19 @@ public class FieldNamingPolicyTest {
   @Test
   public void testUpperCaseFirstLetter() {
     // Map from original -> expected
-    String[][] argumentPairs =  {
-      { "a", "A" },
-      { "ab", "Ab" },
-      { "AB", "AB" },
-      { "_a", "_A" },
-      { "_ab", "_Ab" },
-      { "__", "__" },
-      { "_1", "_1" },
+    String[][] argumentPairs = {
+      {"a", "A"},
+      {"ab", "Ab"},
+      {"AB", "AB"},
+      {"_a", "_A"},
+      {"_ab", "_Ab"},
+      {"__", "__"},
+      {"_1", "_1"},
       // Not a letter, but has uppercase variant (should not be uppercased)
       // See https://github.com/google/gson/issues/1965
-      { "\u2170", "\u2170" },
-      { "_\u2170", "_\u2170" },
-      { "\u2170a", "\u2170A" },
+      {"\u2170", "\u2170"},
+      {"_\u2170", "_\u2170"},
+      {"\u2170a", "\u2170A"},
     };
 
     for (String[] pair : argumentPairs) {
@@ -72,9 +72,7 @@ public class FieldNamingPolicyTest {
     }
   }
 
-  /**
-   * Upper-casing policies should be unaffected by default Locale.
-   */
+  /** Upper-casing policies should be unaffected by default Locale. */
   @Test
   public void testUpperCasingLocaleIndependent() throws Exception {
     class Dummy {
@@ -99,25 +97,25 @@ public class FieldNamingPolicyTest {
     try {
       // Verify that default Locale has different case conversion rules
       assertWithMessage("Test setup is broken")
-          .that(name.toUpperCase(Locale.getDefault())).doesNotMatch(expected);
+          .that(name.toUpperCase(Locale.getDefault()))
+          .doesNotMatch(expected);
 
       for (FieldNamingPolicy policy : policies) {
         // Should ignore default Locale
         assertWithMessage("Unexpected conversion for %s", policy)
-            .that(policy.translateName(field)).matches(expected);
+            .that(policy.translateName(field))
+            .matches(expected);
       }
     } finally {
-        Locale.setDefault(oldLocale);
+      Locale.setDefault(oldLocale);
     }
   }
 
-  /**
-   * Lower casing policies should be unaffected by default Locale.
-   */
+  /** Lower casing policies should be unaffected by default Locale. */
   @Test
   public void testLowerCasingLocaleIndependent() throws Exception {
     class Dummy {
-      @SuppressWarnings("unused")
+      @SuppressWarnings({"unused", "ConstantField"})
       int I;
     }
 
@@ -138,15 +136,17 @@ public class FieldNamingPolicyTest {
     try {
       // Verify that default Locale has different case conversion rules
       assertWithMessage("Test setup is broken")
-          .that(name.toLowerCase(Locale.getDefault())).doesNotMatch(expected);
+          .that(name.toLowerCase(Locale.getDefault()))
+          .doesNotMatch(expected);
 
       for (FieldNamingPolicy policy : policies) {
         // Should ignore default Locale
         assertWithMessage("Unexpected conversion for %s", policy)
-            .that(policy.translateName(field)).matches(expected);
+            .that(policy.translateName(field))
+            .matches(expected);
       }
     } finally {
-        Locale.setDefault(oldLocale);
+      Locale.setDefault(oldLocale);
     }
   }
 }

gson/src/test/java/com/google/gson/GenericArrayTypeTest.java

@@ -37,7 +37,9 @@ public class GenericArrayTypeTest {
 
   @Before
   public void setUp() throws Exception {
-    ourType = $Gson$Types.arrayOf($Gson$Types.newParameterizedTypeWithOwner(null, List.class, String.class));
+    ourType =
+        $Gson$Types.arrayOf(
+            $Gson$Types.newParameterizedTypeWithOwner(null, List.class, String.class));
   }
 
   @Test

gson/src/test/java/com/google/gson/GsonBuilderTest.java

@@ -1,257 +1,396 @@
-/*
- * Copyright (C) 2008 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.google.gson;
-
-import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
-
-import com.google.gson.stream.JsonReader;
-import com.google.gson.stream.JsonWriter;
-import java.io.IOException;
-import java.io.StringReader;
-import java.io.StringWriter;
-import java.lang.reflect.Field;
-import java.lang.reflect.Modifier;
-import java.lang.reflect.Type;
-import org.junit.Test;
-
-/**
- * Unit tests for {@link GsonBuilder}.
- *
- * @author Inderjeet Singh
- */
-public class GsonBuilderTest {
-  private static final TypeAdapter<Object> NULL_TYPE_ADAPTER = new TypeAdapter<Object>() {
-    @Override public void write(JsonWriter out, Object value) {
-      throw new AssertionError();
-    }
-    @Override public Object read(JsonReader in) {
-      throw new AssertionError();
-    }
-  };
-
-  @Test
-  public void testCreatingMoreThanOnce() {
-    GsonBuilder builder = new GsonBuilder();
-    Gson gson = builder.create();
-    assertThat(gson).isNotNull();
-    assertThat(builder.create()).isNotNull();
-
-    builder.setFieldNamingStrategy(new FieldNamingStrategy() {
-      @Override public String translateName(Field f) {
-        return "test";
-      }
-    });
-
-    Gson otherGson = builder.create();
-    assertThat(otherGson).isNotNull();
-    // Should be different instances because builder has been modified in the meantime
-    assertThat(gson).isNotSameInstanceAs(otherGson);
-  }
-
-  /**
-   * Gson instances should not be affected by subsequent modification of GsonBuilder
-   * which created them.
-   */
-  @Test
-  public void testModificationAfterCreate() {
-    GsonBuilder gsonBuilder = new GsonBuilder();
-    Gson gson = gsonBuilder.create();
-
-    // Modifications of `gsonBuilder` should not affect `gson` object
-    gsonBuilder.registerTypeAdapter(CustomClass1.class, new TypeAdapter<CustomClass1>() {
-      @Override public CustomClass1 read(JsonReader in) {
-        throw new UnsupportedOperationException();
-      }
-
-      @Override public void write(JsonWriter out, CustomClass1 value) throws IOException {
-        out.value("custom-adapter");
-      }
-    });
-    gsonBuilder.registerTypeHierarchyAdapter(CustomClass2.class, new JsonSerializer<CustomClass2>() {
-      @Override public JsonElement serialize(CustomClass2 src, Type typeOfSrc, JsonSerializationContext context) {
-        return new JsonPrimitive("custom-hierarchy-adapter");
-      }
-    });
-    gsonBuilder.registerTypeAdapter(CustomClass3.class, new InstanceCreator<CustomClass3>() {
-      @Override public CustomClass3 createInstance(Type type) {
-        return new CustomClass3("custom-instance");
-      }
-    });
-
-
-    assertDefaultGson(gson);
-    // New GsonBuilder created from `gson` should not have been affected by changes
-    // to `gsonBuilder` either
-    assertDefaultGson(gson.newBuilder().create());
-
-    // New Gson instance from modified GsonBuilder should be affected by changes
-    assertCustomGson(gsonBuilder.create());
-  }
-
-  private static void assertDefaultGson(Gson gson) {
-    // Should use default reflective adapter
-    String json1 = gson.toJson(new CustomClass1());
-    assertThat(json1).isEqualTo("{}");
-
-    // Should use default reflective adapter
-    String json2 = gson.toJson(new CustomClass2());
-    assertThat(json2).isEqualTo("{}");
-
-    // Should use default instance creator
-    CustomClass3 customClass3 = gson.fromJson("{}", CustomClass3.class);
-    assertThat(customClass3.s).isEqualTo(CustomClass3.NO_ARG_CONSTRUCTOR_VALUE);
-  }
-
-  private static void assertCustomGson(Gson gson) {
-    String json1 = gson.toJson(new CustomClass1());
-    assertThat(json1).isEqualTo("\"custom-adapter\"");
-
-    String json2 = gson.toJson(new CustomClass2());
-    assertThat(json2).isEqualTo("\"custom-hierarchy-adapter\"");
-
-    CustomClass3 customClass3 = gson.fromJson("{}", CustomClass3.class);
-    assertThat(customClass3.s).isEqualTo("custom-instance");
-  }
-
-  static class CustomClass1 { }
-  static class CustomClass2 { }
-  static class CustomClass3 {
-    static final String NO_ARG_CONSTRUCTOR_VALUE = "default instance";
-
-    final String s;
-
-    public CustomClass3(String s) {
-      this.s = s;
-    }
-
-    public CustomClass3() {
-      this(NO_ARG_CONSTRUCTOR_VALUE);
-    }
-  }
-
-  @Test
-  public void testExcludeFieldsWithModifiers() {
-    Gson gson = new GsonBuilder()
-        .excludeFieldsWithModifiers(Modifier.VOLATILE, Modifier.PRIVATE)
-        .create();
-    assertThat(gson.toJson(new HasModifiers())).isEqualTo("{\"d\":\"d\"}");
-  }
-
-  @SuppressWarnings("unused")
-  static class HasModifiers {
-    private String a = "a";
-    volatile String b = "b";
-    private volatile String c = "c";
-    String d = "d";
-  }
-
-  @Test
-  public void testTransientFieldExclusion() {
-    Gson gson = new GsonBuilder()
-        .excludeFieldsWithModifiers()
-        .create();
-    assertThat(gson.toJson(new HasTransients())).isEqualTo("{\"a\":\"a\"}");
-  }
-
-  static class HasTransients {
-    transient String a = "a";
-  }
-
-  @Test
-  public void testRegisterTypeAdapterForCoreType() {
-    Type[] types = {
-        byte.class,
-        int.class,
-        double.class,
-        Short.class,
-        Long.class,
-        String.class,
-    };
-    for (Type type : types) {
-      new GsonBuilder().registerTypeAdapter(type, NULL_TYPE_ADAPTER);
-    }
-  }
-
-  @Test
-  public void testDisableJdkUnsafe() {
-    Gson gson = new GsonBuilder()
-        .disableJdkUnsafe()
-        .create();
-    try {
-      gson.fromJson("{}", ClassWithoutNoArgsConstructor.class);
-      fail("Expected exception");
-    } catch (JsonIOException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo(
-          "Unable to create instance of class com.google.gson.GsonBuilderTest$ClassWithoutNoArgsConstructor; "
-          + "usage of JDK Unsafe is disabled. Registering an InstanceCreator or a TypeAdapter for this type, "
-          + "adding a no-args constructor, or enabling usage of JDK Unsafe may fix this problem.");
-    }
-  }
-
-  private static class ClassWithoutNoArgsConstructor {
-    @SuppressWarnings("unused")
-    public ClassWithoutNoArgsConstructor(String s) {
-    }
-  }
-
-  @Test
-  public void testSetVersionInvalid() {
-    GsonBuilder builder = new GsonBuilder();
-    try {
-      builder.setVersion(Double.NaN);
-      fail();
-    } catch (IllegalArgumentException e) {
-      assertThat(e).hasMessageThat().isEqualTo("Invalid version: NaN");
-    }
-
-    try {
-      builder.setVersion(-0.1);
-      fail();
-    } catch (IllegalArgumentException e) {
-      assertThat(e).hasMessageThat().isEqualTo("Invalid version: -0.1");
-    }
-  }
-
-  @Test
-  public void testDefaultStrictness() throws IOException {
-    GsonBuilder builder = new GsonBuilder();
-    Gson gson = builder.create();
-    assertThat(gson.newJsonReader(new StringReader("{}")).getStrictness()).isEqualTo(Strictness.LEGACY_STRICT);
-    assertThat(gson.newJsonWriter(new StringWriter()).getStrictness()).isEqualTo(Strictness.LEGACY_STRICT);
-  }
-
-  @SuppressWarnings({"deprecation", "InlineMeInliner"}) // for GsonBuilder.setLenient
-  @Test
-  public void testSetLenient() throws IOException {
-    GsonBuilder builder = new GsonBuilder();
-    builder.setLenient();
-    Gson gson = builder.create();
-    assertThat(gson.newJsonReader(new StringReader("{}")).getStrictness()).isEqualTo(Strictness.LENIENT);
-    assertThat(gson.newJsonWriter(new StringWriter()).getStrictness()).isEqualTo(Strictness.LENIENT);
-  }
-
-  @Test
-  public void testSetStrictness() throws IOException {
-    final Strictness STRICTNESS = Strictness.STRICT;
-    GsonBuilder builder = new GsonBuilder();
-    builder.setStrictness(STRICTNESS);
-    Gson gson = builder.create();
-    assertThat(gson.newJsonReader(new StringReader("{}")).getStrictness()).isEqualTo(STRICTNESS);
-    assertThat(gson.newJsonWriter(new StringWriter()).getStrictness()).isEqualTo(STRICTNESS);
-  }
-}
+/*
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.gson;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.fail;
+
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.lang.reflect.Type;
+import java.text.DateFormat;
+import java.util.Date;
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link GsonBuilder}.
+ *
+ * @author Inderjeet Singh
+ */
+public class GsonBuilderTest {
+  private static final TypeAdapter<Object> NULL_TYPE_ADAPTER =
+      new TypeAdapter<Object>() {
+        @Override
+        public void write(JsonWriter out, Object value) {
+          throw new AssertionError();
+        }
+
+        @Override
+        public Object read(JsonReader in) {
+          throw new AssertionError();
+        }
+      };
+
+  @Test
+  public void testCreatingMoreThanOnce() {
+    GsonBuilder builder = new GsonBuilder();
+    Gson gson = builder.create();
+    assertThat(gson).isNotNull();
+    assertThat(builder.create()).isNotNull();
+
+    builder.setFieldNamingStrategy(
+        new FieldNamingStrategy() {
+          @Override
+          public String translateName(Field f) {
+            return "test";
+          }
+        });
+
+    Gson otherGson = builder.create();
+    assertThat(otherGson).isNotNull();
+    // Should be different instances because builder has been modified in the meantime
+    assertThat(gson).isNotSameInstanceAs(otherGson);
+  }
+
+  /**
+   * Gson instances should not be affected by subsequent modification of GsonBuilder which created
+   * them.
+   */
+  @Test
+  public void testModificationAfterCreate() {
+    GsonBuilder gsonBuilder = new GsonBuilder();
+    Gson gson = gsonBuilder.create();
+
+    // Modifications of `gsonBuilder` should not affect `gson` object
+    gsonBuilder.registerTypeAdapter(
+        CustomClass1.class,
+        new TypeAdapter<CustomClass1>() {
+          @Override
+          public CustomClass1 read(JsonReader in) {
+            throw new UnsupportedOperationException();
+          }
+
+          @Override
+          public void write(JsonWriter out, CustomClass1 value) throws IOException {
+            out.value("custom-adapter");
+          }
+        });
+    gsonBuilder.registerTypeHierarchyAdapter(
+        CustomClass2.class,
+        new JsonSerializer<CustomClass2>() {
+          @Override
+          public JsonElement serialize(
+              CustomClass2 src, Type typeOfSrc, JsonSerializationContext context) {
+            return new JsonPrimitive("custom-hierarchy-adapter");
+          }
+        });
+    gsonBuilder.registerTypeAdapter(
+        CustomClass3.class,
+        new InstanceCreator<CustomClass3>() {
+          @Override
+          public CustomClass3 createInstance(Type type) {
+            return new CustomClass3("custom-instance");
+          }
+        });
+
+    assertDefaultGson(gson);
+    // New GsonBuilder created from `gson` should not have been affected by changes
+    // to `gsonBuilder` either
+    assertDefaultGson(gson.newBuilder().create());
+
+    // New Gson instance from modified GsonBuilder should be affected by changes
+    assertCustomGson(gsonBuilder.create());
+  }
+
+  private static void assertDefaultGson(Gson gson) {
+    // Should use default reflective adapter
+    String json1 = gson.toJson(new CustomClass1());
+    assertThat(json1).isEqualTo("{}");
+
+    // Should use default reflective adapter
+    String json2 = gson.toJson(new CustomClass2());
+    assertThat(json2).isEqualTo("{}");
+
+    // Should use default instance creator
+    CustomClass3 customClass3 = gson.fromJson("{}", CustomClass3.class);
+    assertThat(customClass3.s).isEqualTo(CustomClass3.NO_ARG_CONSTRUCTOR_VALUE);
+  }
+
+  private static void assertCustomGson(Gson gson) {
+    String json1 = gson.toJson(new CustomClass1());
+    assertThat(json1).isEqualTo("\"custom-adapter\"");
+
+    String json2 = gson.toJson(new CustomClass2());
+    assertThat(json2).isEqualTo("\"custom-hierarchy-adapter\"");
+
+    CustomClass3 customClass3 = gson.fromJson("{}", CustomClass3.class);
+    assertThat(customClass3.s).isEqualTo("custom-instance");
+  }
+
+  static class CustomClass1 {}
+
+  static class CustomClass2 {}
+
+  static class CustomClass3 {
+    static final String NO_ARG_CONSTRUCTOR_VALUE = "default instance";
+
+    final String s;
+
+    public CustomClass3(String s) {
+      this.s = s;
+    }
+
+    public CustomClass3() {
+      this(NO_ARG_CONSTRUCTOR_VALUE);
+    }
+  }
+
+  @Test
+  public void testExcludeFieldsWithModifiers() {
+    Gson gson =
+        new GsonBuilder().excludeFieldsWithModifiers(Modifier.VOLATILE, Modifier.PRIVATE).create();
+    assertThat(gson.toJson(new HasModifiers())).isEqualTo("{\"d\":\"d\"}");
+  }
+
+  @SuppressWarnings("unused")
+  static class HasModifiers {
+    private String a = "a";
+    volatile String b = "b";
+    private volatile String c = "c";
+    String d = "d";
+  }
+
+  @Test
+  public void testTransientFieldExclusion() {
+    Gson gson = new GsonBuilder().excludeFieldsWithModifiers().create();
+    assertThat(gson.toJson(new HasTransients())).isEqualTo("{\"a\":\"a\"}");
+  }
+
+  static class HasTransients {
+    transient String a = "a";
+  }
+
+  @Test
+  public void testRegisterTypeAdapterForCoreType() {
+    Type[] types = {
+      byte.class, int.class, double.class, Short.class, Long.class, String.class,
+    };
+    for (Type type : types) {
+      new GsonBuilder().registerTypeAdapter(type, NULL_TYPE_ADAPTER);
+    }
+  }
+
+  @Test
+  public void testDisableJdkUnsafe() {
+    Gson gson = new GsonBuilder().disableJdkUnsafe().create();
+    try {
+      gson.fromJson("{}", ClassWithoutNoArgsConstructor.class);
+      fail("Expected exception");
+    } catch (JsonIOException expected) {
+      assertThat(expected)
+          .hasMessageThat()
+          .isEqualTo(
+              "Unable to create instance of class"
+                  + " com.google.gson.GsonBuilderTest$ClassWithoutNoArgsConstructor; usage of JDK"
+                  + " Unsafe is disabled. Registering an InstanceCreator or a TypeAdapter for this"
+                  + " type, adding a no-args constructor, or enabling usage of JDK Unsafe may fix"
+                  + " this problem.");
+    }
+  }
+
+  private static class ClassWithoutNoArgsConstructor {
+    @SuppressWarnings("unused")
+    public ClassWithoutNoArgsConstructor(String s) {}
+  }
+
+  @Test
+  public void testSetVersionInvalid() {
+    GsonBuilder builder = new GsonBuilder();
+    try {
+      builder.setVersion(Double.NaN);
+      fail();
+    } catch (IllegalArgumentException e) {
+      assertThat(e).hasMessageThat().isEqualTo("Invalid version: NaN");
+    }
+
+    try {
+      builder.setVersion(-0.1);
+      fail();
+    } catch (IllegalArgumentException e) {
+      assertThat(e).hasMessageThat().isEqualTo("Invalid version: -0.1");
+    }
+  }
+
+  @Test
+  public void testDefaultStrictness() throws IOException {
+    GsonBuilder builder = new GsonBuilder();
+    Gson gson = builder.create();
+    assertThat(gson.newJsonReader(new StringReader("{}")).getStrictness())
+        .isEqualTo(Strictness.LEGACY_STRICT);
+    assertThat(gson.newJsonWriter(new StringWriter()).getStrictness())
+        .isEqualTo(Strictness.LEGACY_STRICT);
+  }
+
+  @SuppressWarnings({"deprecation", "InlineMeInliner"}) // for GsonBuilder.setLenient
+  @Test
+  public void testSetLenient() throws IOException {
+    GsonBuilder builder = new GsonBuilder();
+    builder.setLenient();
+    Gson gson = builder.create();
+    assertThat(gson.newJsonReader(new StringReader("{}")).getStrictness())
+        .isEqualTo(Strictness.LENIENT);
+    assertThat(gson.newJsonWriter(new StringWriter()).getStrictness())
+        .isEqualTo(Strictness.LENIENT);
+  }
+
+  @Test
+  public void testSetStrictness() throws IOException {
+    final Strictness STRICTNESS = Strictness.STRICT;
+    GsonBuilder builder = new GsonBuilder();
+    builder.setStrictness(STRICTNESS);
+    Gson gson = builder.create();
+    assertThat(gson.newJsonReader(new StringReader("{}")).getStrictness()).isEqualTo(STRICTNESS);
+    assertThat(gson.newJsonWriter(new StringWriter()).getStrictness()).isEqualTo(STRICTNESS);
+  }
+
+  @Test
+  public void testRegisterTypeAdapterForObjectAndJsonElements() {
+    final String ERROR_MESSAGE = "Cannot override built-in adapter for ";
+    Type[] types = {
+      Object.class, JsonElement.class, JsonArray.class,
+    };
+    GsonBuilder gsonBuilder = new GsonBuilder();
+    for (Type type : types) {
+      IllegalArgumentException e =
+          assertThrows(
+              IllegalArgumentException.class,
+              () -> gsonBuilder.registerTypeAdapter(type, NULL_TYPE_ADAPTER));
+      assertThat(e).hasMessageThat().isEqualTo(ERROR_MESSAGE + type);
+    }
+  }
+
+  @Test
+  public void testRegisterTypeHierarchyAdapterJsonElements() {
+    final String ERROR_MESSAGE = "Cannot override built-in adapter for ";
+    Class<?>[] types = {
+      JsonElement.class, JsonArray.class,
+    };
+    GsonBuilder gsonBuilder = new GsonBuilder();
+    for (Class<?> type : types) {
+      IllegalArgumentException e =
+          assertThrows(
+              IllegalArgumentException.class,
+              () -> gsonBuilder.registerTypeHierarchyAdapter(type, NULL_TYPE_ADAPTER));
+
+      assertThat(e).hasMessageThat().isEqualTo(ERROR_MESSAGE + type);
+    }
+    // But registering type hierarchy adapter for Object should be allowed
+    gsonBuilder.registerTypeHierarchyAdapter(Object.class, NULL_TYPE_ADAPTER);
+  }
+
+  @Test
+  public void testSetDateFormatWithInvalidPattern() {
+    GsonBuilder builder = new GsonBuilder();
+    String invalidPattern = "This is an invalid Pattern";
+    IllegalArgumentException e =
+        assertThrows(IllegalArgumentException.class, () -> builder.setDateFormat(invalidPattern));
+    assertThat(e)
+        .hasMessageThat()
+        .isEqualTo("The date pattern '" + invalidPattern + "' is not valid");
+  }
+
+  @Test
+  public void testSetDateFormatWithValidPattern() {
+    GsonBuilder builder = new GsonBuilder();
+    String validPattern = "yyyy-MM-dd";
+    // Should not throw an exception
+    builder.setDateFormat(validPattern);
+  }
+
+  @Test
+  public void testSetDateFormatNullPattern() {
+    GsonBuilder builder = new GsonBuilder();
+    @SuppressWarnings("JavaUtilDate")
+    Date date = new Date(0);
+    String originalFormatted = builder.create().toJson(date);
+
+    String customFormatted = builder.setDateFormat("yyyy-MM-dd").create().toJson(date);
+    assertThat(customFormatted).isNotEqualTo(originalFormatted);
+
+    // `null` should reset the format to the default
+    String resetFormatted = builder.setDateFormat(null).create().toJson(date);
+    assertThat(resetFormatted).isEqualTo(originalFormatted);
+  }
+
+  /**
+   * Tests behavior for an empty date pattern; this behavior is not publicly documented at the
+   * moment.
+   */
+  @Test
+  public void testSetDateFormatEmptyPattern() {
+    GsonBuilder builder = new GsonBuilder();
+    @SuppressWarnings("JavaUtilDate")
+    Date date = new Date(0);
+    String originalFormatted = builder.create().toJson(date);
+
+    String emptyFormatted = builder.setDateFormat("    ").create().toJson(date);
+    // Empty pattern was ignored
+    assertThat(emptyFormatted).isEqualTo(originalFormatted);
+  }
+
+  @SuppressWarnings("deprecation") // for GsonBuilder.setDateFormat(int)
+  @Test
+  public void testSetDateFormatValidStyle() {
+    GsonBuilder builder = new GsonBuilder();
+    int[] validStyles = {DateFormat.FULL, DateFormat.LONG, DateFormat.MEDIUM, DateFormat.SHORT};
+
+    for (int style : validStyles) {
+      // Should not throw an exception
+      builder.setDateFormat(style);
+      builder.setDateFormat(style, style);
+    }
+  }
+
+  @SuppressWarnings("deprecation") // for GsonBuilder.setDateFormat(int)
+  @Test
+  public void testSetDateFormatInvalidStyle() {
+    GsonBuilder builder = new GsonBuilder();
+
+    IllegalArgumentException e =
+        assertThrows(IllegalArgumentException.class, () -> builder.setDateFormat(-1));
+    assertThat(e).hasMessageThat().isEqualTo("Invalid style: -1");
+
+    e = assertThrows(IllegalArgumentException.class, () -> builder.setDateFormat(4));
+    assertThat(e).hasMessageThat().isEqualTo("Invalid style: 4");
+
+    e =
+        assertThrows(
+            IllegalArgumentException.class, () -> builder.setDateFormat(-1, DateFormat.FULL));
+    assertThat(e).hasMessageThat().isEqualTo("Invalid style: -1");
+
+    e =
+        assertThrows(
+            IllegalArgumentException.class, () -> builder.setDateFormat(DateFormat.FULL, -1));
+    assertThat(e).hasMessageThat().isEqualTo("Invalid style: -1");
+  }
+}