diff --git a/gson/src/main/java/com/google/gson/JsonArray.java b/gson/src/main/java/com/google/gson/JsonArray.java
index 963bf0f5..f3697e21 100644
--- a/gson/src/main/java/com/google/gson/JsonArray.java
+++ b/gson/src/main/java/com/google/gson/JsonArray.java
@@ -297,7 +297,7 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
 
   @Override
   public boolean equals(Object o) {
-    return o instanceof JsonArray && ((JsonArray) o).elements.equals(elements);
+    return (o == this) || (o instanceof JsonArray && ((JsonArray) o).elements.equals(elements));
   }
 
   @Override
diff --git a/gson/src/main/java/com/google/gson/JsonNull.java b/gson/src/main/java/com/google/gson/JsonNull.java
index 01f9e95f..14407549 100755
--- a/gson/src/main/java/com/google/gson/JsonNull.java
+++ b/gson/src/main/java/com/google/gson/JsonNull.java
@@ -53,7 +53,7 @@ public final class JsonNull extends JsonElement {
    */
   @Override
   public boolean equals(Object other) {
-    return other instanceof JsonNull;
+    return this == other || other instanceof JsonNull;
   }
   
   /**
diff --git a/gson/src/main/java/com/google/gson/JsonObject.java b/gson/src/main/java/com/google/gson/JsonObject.java
index fcdab9e7..98c43ce6 100644
--- a/gson/src/main/java/com/google/gson/JsonObject.java
+++ b/gson/src/main/java/com/google/gson/JsonObject.java
@@ -191,8 +191,8 @@ public final class JsonObject extends JsonElement {
 
   @Override
   public boolean equals(Object o) {
-    return o instanceof JsonObject
-        && ((JsonObject) o).members.equals(members);
+    return (o == this) || (o instanceof JsonObject
+        && ((JsonObject) o).members.equals(members));
   }
 
   @Override
diff --git a/gson/src/main/java/com/google/gson/JsonPrimitive.java b/gson/src/main/java/com/google/gson/JsonPrimitive.java
index 05406cd0..c39a7bfc 100644
--- a/gson/src/main/java/com/google/gson/JsonPrimitive.java
+++ b/gson/src/main/java/com/google/gson/JsonPrimitive.java
@@ -356,6 +356,8 @@ public final class JsonPrimitive extends JsonElement {
     }
     if (isFloatingPoint(this) && isFloatingPoint(other)) {
       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));
     }
diff --git a/gson/src/test/java/com/google/gson/JsonArrayTest.java b/gson/src/test/java/com/google/gson/JsonArrayTest.java
index d7bbd362..fdbd7883 100644
--- a/gson/src/test/java/com/google/gson/JsonArrayTest.java
+++ b/gson/src/test/java/com/google/gson/JsonArrayTest.java
@@ -32,6 +32,8 @@ public final class JsonArrayTest extends TestCase {
     JsonArray a = new JsonArray();
     JsonArray b = new JsonArray();
 
+    assertEquals(a, a);
+
     a.add(new JsonObject());
     assertFalse(a.equals(b));
     assertFalse(b.equals(a));
diff --git a/gson/src/test/java/com/google/gson/JsonObjectTest.java b/gson/src/test/java/com/google/gson/JsonObjectTest.java
index 3df5a111..17f84738 100644
--- a/gson/src/test/java/com/google/gson/JsonObjectTest.java
+++ b/gson/src/test/java/com/google/gson/JsonObjectTest.java
@@ -138,6 +138,8 @@ public class JsonObjectTest extends TestCase {
     JsonObject a = new JsonObject();
     JsonObject b = new JsonObject();
 
+    assertEquals(a, a);
+
     a.add("foo", new JsonObject());
     assertFalse(a.equals(b));
     assertFalse(b.equals(a));
diff --git a/gson/src/test/java/com/google/gson/JsonPrimitiveTest.java b/gson/src/test/java/com/google/gson/JsonPrimitiveTest.java
index f5e56f3e..ec69de53 100644
--- a/gson/src/test/java/com/google/gson/JsonPrimitiveTest.java
+++ b/gson/src/test/java/com/google/gson/JsonPrimitiveTest.java
@@ -186,6 +186,15 @@ public class JsonPrimitiveTest extends TestCase {
     MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive(5L), new JsonPrimitive(5L));
     MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive('a'), new JsonPrimitive('a'));
     MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive(Float.NaN), new JsonPrimitive(Float.NaN));
+    MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive(Float.NEGATIVE_INFINITY),
+        new JsonPrimitive(Float.NEGATIVE_INFINITY));
+    MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive(Float.POSITIVE_INFINITY),
+        new JsonPrimitive(Float.POSITIVE_INFINITY));
+    MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive(Double.NaN), new JsonPrimitive(Double.NaN));
+    MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive(Double.NEGATIVE_INFINITY),
+        new JsonPrimitive(Double.NEGATIVE_INFINITY));
+    MoreAsserts.assertEqualsAndHashCode(new JsonPrimitive(Double.POSITIVE_INFINITY),
+        new JsonPrimitive(Double.POSITIVE_INFINITY));
     assertFalse(new JsonPrimitive("a").equals(new JsonPrimitive("b")));
     assertFalse(new JsonPrimitive(true).equals(new JsonPrimitive(false)));
     assertFalse(new JsonPrimitive(0).equals(new JsonPrimitive(1)));