diff --git a/gson/src/main/java/com/google/gson/JsonDeserializationContextDefault.java b/gson/src/main/java/com/google/gson/JsonDeserializationContextDefault.java
index c3f56a3e..8a5c9ef5 100644
--- a/gson/src/main/java/com/google/gson/JsonDeserializationContextDefault.java
+++ b/gson/src/main/java/com/google/gson/JsonDeserializationContextDefault.java
@@ -60,7 +60,7 @@ final class JsonDeserializationContextDefault implements JsonDeserializationCont
       JsonDeserializationContext context) throws JsonParseException {
     JsonArrayDeserializationVisitor<T> visitor = new JsonArrayDeserializationVisitor<T>(
         jsonArray, arrayType, navigatorFactory, objectConstructor, deserializers, context);
-    ObjectNavigator on = navigatorFactory.create(null, arrayType);
+    ObjectNavigator on = navigatorFactory.create(new ObjectTypePair(null, arrayType));
     on.accept(visitor);
     return visitor.getTarget();
   }
@@ -69,7 +69,7 @@ final class JsonDeserializationContextDefault implements JsonDeserializationCont
       JsonDeserializationContext context) throws JsonParseException {
     JsonObjectDeserializationVisitor<T> visitor = new JsonObjectDeserializationVisitor<T>(
         jsonObject, typeOfT, navigatorFactory, objectConstructor, deserializers, context);
-    ObjectNavigator on = navigatorFactory.create(null, typeOfT);
+    ObjectNavigator on = navigatorFactory.create(new ObjectTypePair(null, typeOfT));
     on.accept(visitor);
     return visitor.getTarget();
   }
@@ -79,7 +79,7 @@ final class JsonDeserializationContextDefault implements JsonDeserializationCont
       JsonDeserializationContext context) throws JsonParseException {
     JsonObjectDeserializationVisitor<T> visitor = new JsonObjectDeserializationVisitor<T>(
         json, typeOfT, navigatorFactory, objectConstructor, deserializers, context);
-    ObjectNavigator on = navigatorFactory.create(json.getAsObject(), typeOfT);
+    ObjectNavigator on = navigatorFactory.create(new ObjectTypePair(json.getAsObject(), typeOfT));
     on.accept(visitor);
     Object target = visitor.getTarget();
     return (T) target;
diff --git a/gson/src/main/java/com/google/gson/JsonDeserializationVisitor.java b/gson/src/main/java/com/google/gson/JsonDeserializationVisitor.java
index ab0a10c2..23583c39 100644
--- a/gson/src/main/java/com/google/gson/JsonDeserializationVisitor.java
+++ b/gson/src/main/java/com/google/gson/JsonDeserializationVisitor.java
@@ -58,14 +58,15 @@ abstract class JsonDeserializationVisitor<T> implements ObjectNavigator.Visitor
 
   protected abstract T constructTarget();
 
-  public void start(Object node) {
+  public void start(ObjectTypePair node) {
   }
 
-  public void end(Object node) {
+  public void end(ObjectTypePair node) {
   }
 
   @SuppressWarnings("unchecked")
-  public final boolean visitUsingCustomHandler(Object obj, Type objType) {
+  public final boolean visitUsingCustomHandler(ObjectTypePair objTypePair) {
+    Type objType = objTypePair.getType();
     JsonDeserializer deserializer = deserializers.getHandlerFor(objType);
     if (deserializer != null) {
       target = (T) deserializer.deserialize(json, objType, context);
@@ -89,7 +90,7 @@ abstract class JsonDeserializationVisitor<T> implements ObjectNavigator.Visitor
   }
 
   private Object visitChild(Type type, JsonDeserializationVisitor<?> childVisitor) {
-    ObjectNavigator on = factory.create(null, type);
+    ObjectNavigator on = factory.create(new ObjectTypePair(null, type));
     on.accept(childVisitor);
     // the underlying object may have changed during the construction phase
     // This happens primarily because of custom deserializers
diff --git a/gson/src/main/java/com/google/gson/JsonSerializationContextDefault.java b/gson/src/main/java/com/google/gson/JsonSerializationContextDefault.java
index 01f4252f..6e906f53 100644
--- a/gson/src/main/java/com/google/gson/JsonSerializationContextDefault.java
+++ b/gson/src/main/java/com/google/gson/JsonSerializationContextDefault.java
@@ -28,14 +28,14 @@ final class JsonSerializationContextDefault implements JsonSerializationContext
   private final ObjectNavigatorFactory factory;
   private final ParameterizedTypeHandlerMap<JsonSerializer<?>> serializers;
   private final boolean serializeNulls;
-  private final MemoryRefStack<Object> ancestors;
+  private final MemoryRefStack ancestors;
 
   JsonSerializationContextDefault(ObjectNavigatorFactory factory, boolean serializeNulls,
       ParameterizedTypeHandlerMap<JsonSerializer<?>> serializers) {
     this.factory = factory;
     this.serializeNulls = serializeNulls;
     this.serializers = serializers;
-    this.ancestors = new MemoryRefStack<Object>();
+    this.ancestors = new MemoryRefStack();
   }
 
   public JsonElement serialize(Object src) {
@@ -43,7 +43,7 @@ final class JsonSerializationContextDefault implements JsonSerializationContext
   }
 
   public JsonElement serialize(Object src, Type typeOfSrc) {
-    ObjectNavigator on = factory.create(src, typeOfSrc);
+    ObjectNavigator on = factory.create(new ObjectTypePair(src, typeOfSrc));
     JsonSerializationVisitor visitor =
         new JsonSerializationVisitor(factory, serializeNulls, serializers, this, ancestors);
     on.accept(visitor);
diff --git a/gson/src/main/java/com/google/gson/JsonSerializationVisitor.java b/gson/src/main/java/com/google/gson/JsonSerializationVisitor.java
index ed26a383..fbd54df0 100644
--- a/gson/src/main/java/com/google/gson/JsonSerializationVisitor.java
+++ b/gson/src/main/java/com/google/gson/JsonSerializationVisitor.java
@@ -32,12 +32,12 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
   private final ParameterizedTypeHandlerMap<JsonSerializer<?>> serializers;
   private final boolean serializeNulls;
   private final JsonSerializationContext context;
-  private final MemoryRefStack<Object> ancestors;
+  private final MemoryRefStack ancestors;
   private JsonElement root;
 
   JsonSerializationVisitor(ObjectNavigatorFactory factory, boolean serializeNulls,
       ParameterizedTypeHandlerMap<JsonSerializer<?>> serializers,
-      JsonSerializationContext context, MemoryRefStack<Object> ancestors) {
+      JsonSerializationContext context, MemoryRefStack ancestors) {
     this.factory = factory;
     this.serializeNulls = serializeNulls;
     this.serializers = serializers;
@@ -49,7 +49,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
     return null;
   }
 
-  public void start(Object node) {
+  public void start(ObjectTypePair node) {
     if (node == null) {
       return;
     }
@@ -59,7 +59,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
     ancestors.push(node);
   }
 
-  public void end(Object node) {
+  public void end(ObjectTypePair node) {
     if (node != null) {
       ancestors.pop();
     }
@@ -80,7 +80,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
       if (child != null) {
         childType = getActualTypeIfMoreSpecific(childType, child.getClass());
       }
-      addAsArrayElement(childType, child);
+      addAsArrayElement(new ObjectTypePair(child, childType));
     }
   }
 
@@ -92,7 +92,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
         }
       } else {
         Object array = getFieldValue(f, obj);
-        addAsChildOfObject(f, typeOfF, array);
+        addAsChildOfObject(f, new ObjectTypePair(array, typeOfF));
       }
     } catch (CircularReferenceException e) {
       throw e.createDetailedException(f);
@@ -110,7 +110,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
         if (fieldValue != null) {
           typeOfF = getActualTypeIfMoreSpecific(typeOfF, fieldValue.getClass());
         }
-        addAsChildOfObject(f, typeOfF, fieldValue);
+        addAsChildOfObject(f, new ObjectTypePair(fieldValue, typeOfF));
       }
     } catch (CircularReferenceException e) {
       throw e.createDetailedException(f);
@@ -139,8 +139,8 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
     assignToRoot(json);
   }
 
-  private void addAsChildOfObject(Field f, Type fieldType, Object fieldValue) {
-    JsonElement childElement = getJsonElementForChild(fieldType, fieldValue);
+  private void addAsChildOfObject(Field f, ObjectTypePair fieldValuePair) {
+    JsonElement childElement = getJsonElementForChild(fieldValuePair);
     addChildAsElement(f, childElement);
   }
 
@@ -149,17 +149,17 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
     root.getAsJsonObject().add(namingPolicy.translateName(f), childElement);
   }
 
-  private void addAsArrayElement(Type elementType, Object elementValue) {
-    if (elementValue == null) {
+  private void addAsArrayElement(ObjectTypePair elementTypePair) {
+    if (elementTypePair.getObj() == null) {
       root.getAsJsonArray().add(JsonNull.createJsonNull());
     } else {
-      JsonElement childElement = getJsonElementForChild(elementType, elementValue);
+      JsonElement childElement = getJsonElementForChild(elementTypePair);
       root.getAsJsonArray().add(childElement);
     }
   }
 
-  private JsonElement getJsonElementForChild(Type fieldType, Object fieldValue) {
-    ObjectNavigator on = factory.create(fieldValue, fieldType);
+  private JsonElement getJsonElementForChild(ObjectTypePair fieldValueTypePair) {
+    ObjectNavigator on = factory.create(fieldValueTypePair);
     JsonSerializationVisitor childVisitor =
         new JsonSerializationVisitor(factory, serializeNulls, serializers, context, ancestors);
     on.accept(childVisitor);
@@ -167,8 +167,10 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
   }
 
   @SuppressWarnings("unchecked")
-  public boolean visitUsingCustomHandler(Object obj, Type objType) {
+  public boolean visitUsingCustomHandler(ObjectTypePair objTypePair) {
     try {
+      Object obj = objTypePair.getObj();
+      Type objType = objTypePair.getType();
       JsonSerializer serializer = serializers.getHandlerFor(objType);
       if (serializer == null && obj != null) {
         serializer = serializers.getHandlerFor(obj.getClass());
@@ -178,7 +180,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
         if (obj == null) {
           assignToRoot(JsonNull.createJsonNull());
         } else {
-          assignToRoot(invokeCustomHandler(obj, objType, serializer));
+          assignToRoot(invokeCustomHandler(objTypePair, serializer));
         }
         return true;
       }
@@ -189,12 +191,12 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
   }
 
   @SuppressWarnings("unchecked")
-  private JsonElement invokeCustomHandler(Object obj, Type objType, JsonSerializer serializer) {
-    start(obj);
+  private JsonElement invokeCustomHandler(ObjectTypePair objTypePair, JsonSerializer serializer) {
+    start(objTypePair);
     try {
-      return serializer.serialize(obj, objType, context);
+      return serializer.serialize(objTypePair.getObj(), objTypePair.getType(), context);
     } finally {
-      end(obj);
+      end(objTypePair);
     }
   }
 
@@ -211,7 +213,8 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
       }
       JsonSerializer serializer = serializers.getHandlerFor(actualTypeOfField);
       if (serializer != null) {
-        JsonElement child = invokeCustomHandler(obj, actualTypeOfField, serializer);
+        ObjectTypePair objTypePair = new ObjectTypePair(obj, actualTypeOfField);
+        JsonElement child = invokeCustomHandler(objTypePair, serializer);
         addChildAsElement(f, child);
         return true;
       }
diff --git a/gson/src/main/java/com/google/gson/MemoryRefStack.java b/gson/src/main/java/com/google/gson/MemoryRefStack.java
index 2c41ff1e..7db962fc 100644
--- a/gson/src/main/java/com/google/gson/MemoryRefStack.java
+++ b/gson/src/main/java/com/google/gson/MemoryRefStack.java
@@ -25,8 +25,8 @@ import java.util.Stack;
  *
  * @author Joel Leitch
  */
-final class MemoryRefStack<T> {
-  private final Stack<T> stack = new Stack<T>();
+final class MemoryRefStack {
+  private final Stack<ObjectTypePair> stack = new Stack<ObjectTypePair>();
 
   /**
    * Adds a new element to the top of the stack.
@@ -34,7 +34,7 @@ final class MemoryRefStack<T> {
    * @param obj the object to add to the stack
    * @return the object that was added
    */
-  public T push(T obj) {
+  public ObjectTypePair push(ObjectTypePair obj) {
     Preconditions.checkNotNull(obj);
 
     return stack.push(obj);
@@ -46,7 +46,7 @@ final class MemoryRefStack<T> {
    * @return the element being removed from the stack
    * @throws java.util.EmptyStackException thrown if the stack is empty
    */
-  public T pop() {
+  public ObjectTypePair pop() {
     return stack.pop();
   }
 
@@ -60,7 +60,7 @@ final class MemoryRefStack<T> {
    * @return the item from the top of the stack
    * @throws java.util.EmptyStackException thrown if the stack is empty
    */
-  public T peek() {
+  public ObjectTypePair peek() {
     return stack.peek();
   }
 
@@ -71,13 +71,13 @@ final class MemoryRefStack<T> {
    * @param obj the object to search for in the stack
    * @return true if this object is already in the stack otherwise false
    */
-  public boolean contains(T obj) {
+  public boolean contains(ObjectTypePair obj) {
     if (obj == null) {
       return false;
     }
 
-    for (T stackObject : stack) {
-      if (obj == stackObject) {
+    for (ObjectTypePair stackObject : stack) {
+      if (stackObject.getObj() == obj.getObj() && stackObject.getType().equals(obj.getType()) ) {
         return true;
       }
     }
diff --git a/gson/src/main/java/com/google/gson/ObjectNavigator.java b/gson/src/main/java/com/google/gson/ObjectNavigator.java
index dd82c2cb..7a56756b 100644
--- a/gson/src/main/java/com/google/gson/ObjectNavigator.java
+++ b/gson/src/main/java/com/google/gson/ObjectNavigator.java
@@ -29,8 +29,8 @@ import java.lang.reflect.Type;
 final class ObjectNavigator {
 
   public interface Visitor {
-    public void start(Object node);
-    public void end(Object node);
+    public void start(ObjectTypePair node);
+    public void end(ObjectTypePair node);
 
     /**
      * This is called before the object navigator starts visiting the current object
@@ -56,7 +56,7 @@ final class ObjectNavigator {
      * This is called to visit an object using a custom handler
      * @return true if a custom handler exists, false otherwise
      */
-    public boolean visitUsingCustomHandler(Object obj, Type objType);
+    public boolean visitUsingCustomHandler(ObjectTypePair objTypePair);
 
     /**
      * This is called to visit a field of the current object using a custom handler
@@ -72,20 +72,17 @@ final class ObjectNavigator {
   }
 
   private final ExclusionStrategy exclusionStrategy;
-  private final Object obj;
-  private final Type objType;
+  private final ObjectTypePair objTypePair;
 
   /**
-   * @param obj The object being navigated
-   * @param objType The (fully genericized) type of the object being navigated
+   * @param objTypePair The object,type (fully genericized) being navigated
    * @param exclusionStrategy the concrete strategy object to be used to
    *        filter out fields of an object.
    */
-  ObjectNavigator(Object obj, Type objType, ExclusionStrategy exclusionStrategy) {
+  ObjectNavigator(ObjectTypePair objTypePair, ExclusionStrategy exclusionStrategy) {
     Preconditions.checkNotNull(exclusionStrategy);
 
-    this.obj = obj;
-    this.objType = objType;
+    this.objTypePair = objTypePair;
     this.exclusionStrategy = exclusionStrategy;
   }
 
@@ -94,20 +91,21 @@ final class ObjectNavigator {
    * If a field is null, it does not get visited.
    */
   public void accept(Visitor visitor) {
-    boolean visitedWithCustomHandler = visitor.visitUsingCustomHandler(obj, objType);
+    boolean visitedWithCustomHandler = visitor.visitUsingCustomHandler(objTypePair);
     if (!visitedWithCustomHandler) {
+      Object obj = objTypePair.getObj();
       Object objectToVisit = (obj == null) ? visitor.getTarget() : obj;
       if (objectToVisit == null) {
         return;
       }
-      TypeInfo objTypeInfo = new TypeInfo(objType);
+      TypeInfo objTypeInfo = new TypeInfo(objTypePair.getType());
       if (exclusionStrategy.shouldSkipClass(objTypeInfo.getRawClass())) {
         return;
       }
-      visitor.start(obj);  
+      visitor.start(objTypePair);  
       try {
         if (objTypeInfo.isArray()) {
-          visitor.visitArray(objectToVisit, objType);
+          visitor.visitArray(objectToVisit, objTypePair.getType());
         } else if (objTypeInfo.getActualType() == Object.class
             && isPrimitiveOrString(objectToVisit)) {
           // TODO(Joel): this is only used for deserialization of "primitves"
@@ -128,7 +126,7 @@ final class ObjectNavigator {
           }
         }
       } finally {
-        visitor.end(obj);
+        visitor.end(objTypePair);
       }
     }
   }
@@ -146,7 +144,7 @@ final class ObjectNavigator {
       if (exclusionStrategy.shouldSkipField(f)) {
         continue; // skip
       } else {
-        TypeInfo fieldTypeInfo = TypeInfoFactory.getTypeInfoForField(f, objType);
+        TypeInfo fieldTypeInfo = TypeInfoFactory.getTypeInfoForField(f, objTypePair.getType());
         Type actualTypeOfField = fieldTypeInfo.getActualType();
         boolean visitedWithCustomHandler = 
             visitor.visitFieldUsingCustomHandler(f, actualTypeOfField, obj);
diff --git a/gson/src/main/java/com/google/gson/ObjectNavigatorFactory.java b/gson/src/main/java/com/google/gson/ObjectNavigatorFactory.java
index c803193a..69fef7ce 100644
--- a/gson/src/main/java/com/google/gson/ObjectNavigatorFactory.java
+++ b/gson/src/main/java/com/google/gson/ObjectNavigatorFactory.java
@@ -16,8 +16,6 @@
 
 package com.google.gson;
 
-import java.lang.reflect.Type;
-
 /**
  * A factory class used to simplify {@link ObjectNavigator} creation.
  * This object holds on to a reference of the {@link ExclusionStrategy}
@@ -48,15 +46,13 @@ final class ObjectNavigatorFactory {
    * Creates a new {@link ObjectNavigator} for this {@code srcObject},
    * {@code type} pair.
    *
-   * @param srcObject object to navigate
-   * @param type the "actual" type of this {@code srcObject}.  NOTE: this can
-   *        be a {@link java.lang.reflect.ParameterizedType} rather than a {@link Class}.
+   * @param objTypePair The object,type (fully genericized) being navigated
    * @return a new instance of a {@link ObjectNavigator} ready to navigate the
    *         {@code srcObject} while taking into consideration the
    *         {@code type}.
    */
-  public ObjectNavigator create(Object srcObject, Type type) {
-    return new ObjectNavigator(srcObject, type, strategy);
+  public ObjectNavigator create(ObjectTypePair objTypePair) {
+    return new ObjectNavigator(objTypePair, strategy);
   }
 
   FieldNamingStrategy getFieldNamingPolicy() {
diff --git a/gson/src/main/java/com/google/gson/ObjectTypePair.java b/gson/src/main/java/com/google/gson/ObjectTypePair.java
new file mode 100644
index 00000000..79b72182
--- /dev/null
+++ b/gson/src/main/java/com/google/gson/ObjectTypePair.java
@@ -0,0 +1,47 @@
+package com.google.gson;
+
+import java.lang.reflect.Type;
+
+ final class ObjectTypePair {
+  private final Object obj;
+  private final Type type;
+  public ObjectTypePair(Object obj, Type type) {
+    this.obj = obj;
+    this.type = type;
+  }
+  public Object getObj() {
+    return obj;
+  }
+  public Type getType() {
+    return type;
+  }
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((obj == null) ? 0 : obj.hashCode());
+    result = prime * result + ((type == null) ? 0 : type.hashCode());
+    return result;
+  }
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    ObjectTypePair other = (ObjectTypePair) obj;
+    if (this.obj == null) {
+      if (other.obj != null)
+        return false;
+    } else if (!this.obj.equals(other.obj))
+      return false;
+    if (type == null) {
+      if (other.type != null)
+        return false;
+    } else if (!type.equals(other.type))
+      return false;
+    return true;
+  }
+}
diff --git a/gson/src/test/java/com/google/gson/MemoryRefStackTest.java b/gson/src/test/java/com/google/gson/MemoryRefStackTest.java
index a05d2b8c..908bfebb 100644
--- a/gson/src/test/java/com/google/gson/MemoryRefStackTest.java
+++ b/gson/src/test/java/com/google/gson/MemoryRefStackTest.java
@@ -28,12 +28,12 @@ import java.util.EmptyStackException;
  * @author Joel Leitch
  */
 public class MemoryRefStackTest extends TestCase {
-  private MemoryRefStack<MockObject> stack;
+  private MemoryRefStack stack;
 
   @Override
   protected void setUp() throws Exception {
     super.setUp();
-    stack = new MemoryRefStack<MockObject>();
+    stack = new MemoryRefStack();
   }
 
   public void testPeekEmptyStack() throws Exception {
@@ -43,7 +43,7 @@ public class MemoryRefStackTest extends TestCase {
   }
 
   public void testPushPeekAndPop() throws Exception {
-    MockObject obj = new MockObject();
+    ObjectTypePair obj = new ObjectTypePair(this, getClass());
 
     assertEquals(obj, stack.push(obj));
     assertEquals(obj, stack.peek());
@@ -51,7 +51,7 @@ public class MemoryRefStackTest extends TestCase {
   }
 
   public void testPopTooMany() throws Exception {
-    MockObject obj = new MockObject();
+    ObjectTypePair obj = new ObjectTypePair(this, getClass());
     stack.push(obj);
     assertEquals(obj, stack.pop());
 
@@ -61,8 +61,8 @@ public class MemoryRefStackTest extends TestCase {
   }
 
   public void testContains() throws Exception {
-    MockObject objA = new MockObject();
-    MockObject objB = new MockObject();
+    ObjectTypePair objA = new ObjectTypePair(new MockObject(), MockObject.class);
+    ObjectTypePair objB = new ObjectTypePair(new MockObject(), MockObject.class);
     assertEquals(objA, objB);
 
     stack.push(objA);
diff --git a/gson/src/test/java/com/google/gson/functional/InterfaceTest.java b/gson/src/test/java/com/google/gson/functional/InterfaceTest.java
index f8caf773..6851f1e9 100644
--- a/gson/src/test/java/com/google/gson/functional/InterfaceTest.java
+++ b/gson/src/test/java/com/google/gson/functional/InterfaceTest.java
@@ -32,6 +32,7 @@ public class InterfaceTest extends TestCase {
   private Gson gson;
   private TestObject obj;
 
+  @Override
   protected void setUp() throws Exception {
     super.setUp();
     gson = new Gson();