Fix error prone warns (#2319)

* Adds a javadoc summary to the methods in the `SerializedName` annotation

Fixes the `MissingSummary` warn given by ErrorProne

* Adds a javadoc summary to the methods of the `ExclusionStrategy` annotation

 Fixes the `MissingSummary` warn given by ErrorProne

* Adds a javadoc summary to `getDeclaringClass()` and `getName()` methods of the `FieldAttributes` class

 Fixes the `MissingSummary` warn given by ErrorProne

* Adds a javadoc summary to `getMajorJavaVersion()` and `isJava9OrLater()` methods of the `JavaVersion` class

 Fixes the `MissingSummary` warn given by ErrorProne

* Adds a comment in the empty catch block of the `AccessChecker:101` class

 Fixes the `EmptyCatch` warn given by ErrorProne

* Adds a comment in the empty catch block of the `DefaultDateTypeAdapter:158` class

 Fixes the `EmptyCatch` warn given by ErrorProne

* Adds a comment in the empty catch blocks of the `UnsafeAllocator:(67|92|113)` class

 Fixes the `EmptyCatch` warn given by ErrorProne

* Adds a comment in the empty catch block of the `DateTypeAdapter:85` class

 Fixes the `EmptyCatch` warn given by ErrorProne

* Fixes javadoc param of the `deserialize(...)` method of the `JsonDeserializer` interface

 Fixes the `InvalidParam` warn given by ErrorProne

* Adds a charset `StandardCharsets.UTF_8` in the `resourceToString()` method of the `ParseBenchmark` class

Fixes the `DefaultCharset` warn given by ErrorProne

* Fixes a typo

* Implements review feedback

* Adds blank line before @ tag.

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

@@ -93,12 +93,16 @@ package com.google.gson;
 public interface ExclusionStrategy {
 
   /**
+   * Decides if a field should be skipped during serialization or deserialization.
+   *
    * @param f the field object that is under test
    * @return true if the field should be ignored; otherwise false
    */
   public boolean shouldSkipField(FieldAttributes f);
 
   /**
+   * Decides if a class should be serialized or deserialized
+   *
    * @param clazz the class object that is under test
    * @return true if the class should be ignored; otherwise false
    */

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

@@ -46,6 +46,8 @@ public final class FieldAttributes {
   }
 
   /**
+   * Gets the declaring Class that contains this field
+   *
    * @return the declaring class that contains this field
    */
   public Class<?> getDeclaringClass() {
@@ -53,6 +55,8 @@ public final class FieldAttributes {
   }
 
   /**
+   * Gets the name of the field
+   *
    * @return the name of the field
    */
   public String getName() {

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

@@ -89,7 +89,7 @@ public interface JsonDeserializer<T> {
    * @param json The Json data being deserialized
    * @param typeOfT The type of the Object to deserialize to
    * @return a deserialized object of the specified type typeOfT which is a subclass of {@code T}
-   * @throws JsonParseException if json is not in the expected format of {@code typeofT}
+   * @throws JsonParseException if json is not in the expected format of {@code typeOfT}
    */
   public T deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
       throws JsonParseException;

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

@@ -83,10 +83,14 @@ import java.lang.annotation.Target;
 public @interface SerializedName {
 
   /**
+   * The desired name of the field when it is serialized or deserialized.
+   *
    * @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
+   *
    * @return the alternative names of the field when it is deserialized
    */
   String[] alternate() default {};

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

@@ -75,6 +75,8 @@ public final class JavaVersion {
   }
 
   /**
+   * Gets the major Java version
+   *
    * @return the major Java version, i.e. '8' for Java 1.8, '9' for Java 9 etc.
    */
   public static int getMajorJavaVersion() {
@@ -82,6 +84,8 @@ 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.
    */
   public static boolean isJava9OrLater() {

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

@@ -98,6 +98,7 @@ public class ReflectionAccessFilterHelper {
             }
           };
         } catch (NoSuchMethodException ignored) {
+          // OK: will assume everything is accessible
         }
       }
 

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

@@ -64,6 +64,7 @@ public abstract class UnsafeAllocator {
         }
       };
     } catch (Exception ignored) {
+      // OK: try the next way
     }
 
     // try dalvikvm, post-gingerbread
@@ -88,6 +89,7 @@ public abstract class UnsafeAllocator {
         }
       };
     } catch (Exception ignored) {
+      // OK: try the next way
     }
 
     // try dalvikvm, pre-gingerbread
@@ -108,6 +110,7 @@ public abstract class UnsafeAllocator {
         }
       };
     } catch (Exception ignored) {
+      // OK: try the next way
     }
 
     // give up

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

@@ -81,7 +81,9 @@ public final class DateTypeAdapter extends TypeAdapter<Date> {
       for (DateFormat dateFormat : dateFormats) {
         try {
           return dateFormat.parse(s);
-        } catch (ParseException ignored) {}
+        } catch (ParseException ignored) {
+          // OK: try the next format
+        }
       }
     }
     try {

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

@@ -154,7 +154,9 @@ public final class DefaultDateTypeAdapter<T extends Date> extends TypeAdapter<T>
       for (DateFormat dateFormat : dateFormats) {
         try {
           return dateFormat.parse(s);
-        } catch (ParseException ignored) {}
+        } catch (ParseException ignored) {
+          // OK: try the next format
+        }
       }
     }
 

metrics/src/main/java/com/google/gson/metrics/ParseBenchmark.java

@@ -40,6 +40,7 @@ import java.io.Reader;
 import java.io.StringWriter;
 import java.lang.reflect.Type;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.List;
@@ -137,7 +138,7 @@ public final class ParseBenchmark {
     ZipFile zipFile = new ZipFile(getResourceFile("/ParseBenchmarkData.zip"));
     try {
       ZipEntry zipEntry = zipFile.getEntry(fileName);
-      Reader reader = new InputStreamReader(zipFile.getInputStream(zipEntry));
+      Reader reader = new InputStreamReader(zipFile.getInputStream(zipEntry), StandardCharsets.UTF_8);
       char[] buffer = new char[8192];
       StringWriter writer = new StringWriter();
       int count;