Fix Javadoc warnings and errors (#2040)

extras/src/main/java/com/google/gson/interceptors/Intercept.java

@@ -28,8 +28,8 @@ import java.lang.annotation.Target;
  * after it has been deserialized from Json.
  * Here is an example of how this annotation is used:
  * <p>Here is an example of how this annotation is used:
- * <p><pre>
- * &#64Intercept(postDeserialize=UserValidator.class)
+ * <pre>
+ * &#64;Intercept(postDeserialize=UserValidator.class)
  * public class User {
  *   String name;
  *   String password;
@@ -47,7 +47,7 @@ import java.lang.annotation.Target;
  *     }
  *   }
  * }
- * </pre></p>
+ * </pre>
  *
  * @author Inderjeet Singh
  */

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

@@ -76,7 +76,7 @@ import com.google.gson.stream.MalformedJsonException;
  * MyType target = new MyType();
  * String json = gson.toJson(target); // serializes target to Json
  * MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2
- * </pre></p>
+ * </pre>
  *
  * <p>If the object that your are serializing/deserializing is a {@code ParameterizedType}
  * (i.e. contains at least one type parameter and may be an array) then you must use the
@@ -91,7 +91,7 @@ import com.google.gson.stream.MalformedJsonException;
  * Gson gson = new Gson();
  * String json = gson.toJson(target, listType);
  * List&lt;String&gt; target2 = gson.fromJson(json, listType);
- * </pre></p>
+ * </pre>
  *
  * <p>See the <a href="https://sites.google.com/site/gson/gson-user-guide">Gson User Guide</a>
  * for a more complete set of examples.</p>
@@ -548,7 +548,7 @@ public final class Gson {
    *  read or written.
    * @param skipPast The type adapter factory that needs to be skipped while searching for
    *   a matching type adapter. In most cases, you should just pass <i>this</i> (the type adapter
-   *   factory from where {@link #getDelegateAdapter} method is being invoked).
+   *   factory from where {@code getDelegateAdapter} method is being invoked).
    * @param type Type for which the delegate adapter is being searched for.
    *
    * @since 2.2

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

@@ -61,7 +61,7 @@ import static com.google.gson.Gson.DEFAULT_SPECIALIZE_FLOAT_VALUES;
  *     .setPrettyPrinting()
  *     .setVersion(1.0)
  *     .create();
- * </pre></p>
+ * </pre>
  *
  * <p>NOTES:
  * <ul>
@@ -69,8 +69,7 @@ import static com.google.gson.Gson.DEFAULT_SPECIALIZE_FLOAT_VALUES;
  * <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>
- *  </ul>
- * </p>
+ * </ul>
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -251,6 +250,7 @@ public final class GsonBuilder {
    *   original.put(new Point(8, 8), "b");
    *   System.out.println(gson.toJson(original, type));
    * }
+   * </pre>
    *
    * The JSON output would look as follows:
    * <pre>   {@code

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

@@ -26,7 +26,7 @@ import java.lang.reflect.Type;
  * <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>
  *
- * <p><pre>
+ * <pre>
  * public class Id&lt;T&gt; {
  *   private final Class&lt;T&gt; clazz;
  *   private final long value;
@@ -40,20 +40,20 @@ import java.lang.reflect.Type;
  *     return value;
  *   }
  * }
- * </pre></p>
+ * </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><pre>
+ * <pre>
  * class IdSerializer implements JsonSerializer&lt;Id&gt;() {
  *   public JsonElement serialize(Id id, Type typeOfId, JsonSerializationContext context) {
  *     return new JsonPrimitive(id.getValue());
  *   }
  * }
- * </pre></p>
+ * </pre>
  *
  * <p>You will also need to register {@code IdSerializer} with Gson as follows:</p>
  * <pre>

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

@@ -65,7 +65,6 @@ public interface ToNumberStrategy {
    *
    * @param in JSON reader to read a number from
    * @return number read from the JSON reader.
-   * @throws IOException
    */
   public Number readNumber(JsonReader in) throws IOException;
 }

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

@@ -32,14 +32,14 @@ import java.lang.annotation.Target;
  * method.</p>
  *
  * <p>Here is an example of how this annotation is meant to be used:
- * <p><pre>
+ * <pre>
  * public class User {
  *   &#64;Expose private String firstName;
  *   &#64;Expose(serialize = false) private String lastName;
  *   &#64;Expose (serialize = false, deserialize = false) private String emailAddress;
  *   private String password;
  * }
- * </pre></p>
+ * </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

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

@@ -170,7 +170,7 @@ import java.util.Arrays;
  * precision loss, extremely large values should be written and read as strings
  * in JSON.
  *
- * <a id="nonexecuteprefix"/><h3>Non-Execute Prefix</h3>
+ * <h3 id="nonexecuteprefix">Non-Execute Prefix</h3>
  * Web servers that serve private data using JSON may be vulnerable to <a
  * href="http://en.wikipedia.org/wiki/JSON#Cross-site_request_forgery">Cross-site
  * request forgery</a> attacks. In such an attack, a malicious site gains access

proto/src/main/java/com/google/gson/protobuf/ProtoTypeAdapter.java

@@ -37,7 +37,6 @@ import com.google.protobuf.Descriptors.FieldDescriptor;
 import com.google.protobuf.DynamicMessage;
 import com.google.protobuf.Extension;
 import com.google.protobuf.Message;
-
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -76,7 +75,7 @@ public class ProtoTypeAdapter
   /**
    * Determines how enum <u>values</u> should be serialized.
    */
-  public static enum EnumSerialization {
+  public enum EnumSerialization {
     /**
      * Serializes and deserializes enum values using their <b>number</b>. When this is used, custom
      * value names set on enums are ignored.
@@ -117,12 +116,12 @@ public class ProtoTypeAdapter
      * For example, if you use the following parameters: {@link CaseFormat#LOWER_UNDERSCORE},
      * {@link CaseFormat#LOWER_CAMEL}, the following conversion will occur:
      *
-     * <pre>
+     * <pre>{@code
      * PROTO     <->  JSON
      * my_field       myField
      * foo            foo
      * n__id_ct       nIdCt
-     * </pre>
+     * }</pre>
      */
     public Builder setFieldNameSerializationFormat(CaseFormat fromFieldNameFormat,
         CaseFormat toFieldNameFormat) {