diff --git a/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/Message.java b/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/Message.java
index b83e5a6296f6..cc65536d8a84 100644
--- a/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/Message.java
+++ b/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/Message.java
@@ -37,7 +37,7 @@
  * a key {@code iana.org/language_tag} and value {@code en} could be added to messages to mark them
  * as readable by an English-speaking subscriber.
  *
- * <p>To be published a message must have a non-empty payload, or at least one attribute.
+ * <p>To be published, a message must have a non-empty payload, or at least one attribute.
  *
  * @see <a href="https://cloud.google.com/pubsub/overview#data_model">Pub/Sub Data Model</a>
  */
@@ -64,11 +64,11 @@ private static final class InternalByteArray extends ByteArray {
 
     private static final long serialVersionUID = -3330181485911805428L;
 
-    protected InternalByteArray(ByteString byteString) {
+    InternalByteArray(ByteString byteString) {
       super(byteString);
     }
 
-    protected InternalByteArray(ByteArray byteArray) {
+    InternalByteArray(ByteArray byteArray) {
       super(byteArray);
     }
 
@@ -244,17 +244,24 @@ public ByteArray payload() {
     return payload;
   }
 
+  final boolean baseEquals(Message message) {
+    return Objects.equals(id, message.id)
+        && Objects.equals(payload, message.payload)
+        && Objects.equals(attributes, message.attributes)
+        && Objects.equals(publishTime, message.publishTime);
+  }
+
   @Override
   public boolean equals(Object obj) {
     return obj == this
         || obj != null
         && obj.getClass().equals(Message.class)
-        && Objects.equals(toPb(), ((Message) obj).toPb());
+        && baseEquals((Message) obj);
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(serialVersionUID, id, payload, attributes, publishTime);
+    return Objects.hash(id, payload, attributes, publishTime);
   }
 
   @Override
diff --git a/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/ReceivedMessage.java b/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/ReceivedMessage.java
index c3cb705cb6d7..1af9a5ae46d2 100644
--- a/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/ReceivedMessage.java
+++ b/gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/ReceivedMessage.java
@@ -27,7 +27,16 @@
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 
-public class ReceivedMessage extends Message {
+/**
+ * A Google Cloud Pub/Sub received message. A received message has all the information in
+ * {@link Message} as well as the acknowledge id. The ack id can be used to acknowledge the received
+ * message.
+ *
+ * <p>{@code ReceivedMessage} also adds a layer of service-related functionality over
+ * {@link Message} that help manage received messages (see {@link #ack()}, {@link #nack()} and
+ * {@link #modifyAckDeadline(int, TimeUnit)}).
+ */
+public final class ReceivedMessage extends Message {
 
   private static final long serialVersionUID = -4178477763916251733L;
 
@@ -124,48 +133,109 @@ public int hashCode() {
 
   @Override
   public boolean equals(Object obj) {
-    if (this == obj) {
+    if (obj == this) {
       return true;
     }
-    if (obj == null || getClass() != obj.getClass()) {
+    if (obj == null || !obj.getClass().equals(ReceivedMessage.class)) {
       return false;
     }
     ReceivedMessage other = (ReceivedMessage) obj;
-    return Objects.equals(toPb(), other.toPb()) && Objects.equals(options, other.options);
+    return baseEquals(other) && Objects.equals(options, other.options);
   }
 
-  public PubSub pubSub() {
+  /**
+   * Returns the received message's {@code PubSub} object used to issue requests.
+   */
+  public PubSub pubsub() {
     return pubsub;
   }
 
+  /**
+   * Returns the name of the subscription this message was received from.
+   */
   public String subscription() {
     return subscription;
   }
 
+  /**
+   * Returns the acknowledge id of the message. The ack id can be used to acknowledge the received
+   * message.
+   */
   public String ackId() {
     return ackId;
   }
 
+  /**
+   * Acknowledges the current message.
+   *
+   * @throws PubSubException upon failure, or if the subscription was not found
+   */
   public void ack() {
     pubsub.ack(subscription, ackId);
   }
 
+  /**
+   * Sends a request to acknowledge the current message. The method returns a {@code Future} object
+   * that can be used to wait for the acknowledge operation to be completed.
+   *
+   * @throws PubSubException upon failure, or if the subscription was not found
+   */
   public Future<Void> ackAsync() {
     return pubsub.ackAsync(subscription, ackId);
   }
 
+  /**
+   * "Nacks" the current message. This method corresponds to calling
+   * {@link #modifyAckDeadline(int, TimeUnit)} with a deadline of 0.
+   *
+   * @throws PubSubException upon failure, or if the subscription was not found
+   */
   public void nack() {
     pubsub.nack(subscription, ackId);
   }
 
+  /**
+   * Sends a request to "nack" the current message. This method corresponds to calling
+   * {@link #modifyAckDeadlineAsync(int, TimeUnit)} with a deadline of 0. The method returns a
+   * {@code Future} object that can be used to wait for the "nack" operation to be completed.
+   *
+   * @throws PubSubException upon failure, or if the subscription was not found
+   */
   public Future<Void> nackAsync() {
     return pubsub.nackAsync(subscription, ackId);
   }
 
+  /**
+   * Modifies the acknowledge deadline of the current message. {@code deadline} must be &gt;= 0 and
+   * is the new deadline with respect to the time the modify request was received by the Pub/Sub
+   * service. For example, if {@code deadline} is 10 and {@code unit} is {@link TimeUnit#SECONDS},
+   * the new ack deadline will expire 10 seconds after the modify request was received by the
+   * service. Specifying 0 may be used to make the message available for another pull request
+   * (corresponds to calling {@link #nack()}.
+   *
+   * @param deadline the new deadline, relative to the time the modify request is received by the
+   *     Pub/Sub service
+   * @param unit {@code deadline} time unit
+   * @throws PubSubException upon failure, or if the subscription was not found
+   */
   public void modifyAckDeadline(int deadline, TimeUnit unit) {
     pubsub.modifyAckDeadline(subscription, deadline, unit, ackId);
   }
 
+  /**
+   * Sends a request to modify the acknowledge deadline of the given messages. {@code deadline}
+   * must be &gt;= 0 and is the new deadline with respect to the time the modify request was
+   * received by the Pub/Sub service. For example, if {@code deadline} is 10 and {@code unit} is
+   * {@link TimeUnit#SECONDS}, the new ack deadline will expire 10 seconds after the modify request
+   * was received by the service. Specifying 0 may be used to make the message available for another
+   * pull request (corresponds to calling {@link #nackAsync()}. The method returns a {@code Future}
+   * object that can be used to wait for the modify operation to be completed.
+   *
+   * @param deadline the new deadline, relative to the time the modify request is received by the
+   *     Pub/Sub service
+   * @param unit {@code deadline} time unit
+   * @throws PubSubException upon failure, or if the subscription was not found
+   */
   public Future<Void> modifyAckDeadlineAsync(int deadline, TimeUnit unit) {
     return pubsub.modifyAckDeadlineAsync(subscription, deadline, unit, ackId);
   }
@@ -175,10 +245,10 @@ private void readObject(ObjectInputStream input) throws IOException, ClassNotFou
     this.pubsub = options.service();
   }
 
-  static ReceivedMessage fromPb(PubSub storage, String subscription,
+  static ReceivedMessage fromPb(PubSub pubsub, String subscription,
       com.google.pubsub.v1.ReceivedMessage msgPb) {
     Message message = fromPb(msgPb.getMessage());
     String ackId = msgPb.getAckId();
-    return new Builder(subscription, ackId, storage, new BuilderImpl(message)).build();
+    return new Builder(subscription, ackId, pubsub, new BuilderImpl(message)).build();
   }
 }
diff --git a/gcloud-java-pubsub/src/test/java/com/google/cloud/pubsub/ReceivedMessageTest.java b/gcloud-java-pubsub/src/test/java/com/google/cloud/pubsub/ReceivedMessageTest.java
new file mode 100644
index 000000000000..f21fbd106674
--- /dev/null
+++ b/gcloud-java-pubsub/src/test/java/com/google/cloud/pubsub/ReceivedMessageTest.java
@@ -0,0 +1,187 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * 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.cloud.pubsub;
+
+import static org.easymock.EasyMock.createMock;
+import static org.easymock.EasyMock.createStrictMock;
+import static org.easymock.EasyMock.expect;
+import static org.easymock.EasyMock.replay;
+import static org.easymock.EasyMock.verify;
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+
+import com.google.api.client.util.Charsets;
+import com.google.cloud.ByteArray;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.util.concurrent.Futures;
+
+import org.easymock.EasyMock;
+import org.junit.After;
+import org.junit.Test;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+
+public class ReceivedMessageTest {
+
+  private static final String SUBSCRIPTION = "subscription";
+  private static final String ACK_ID = "ackId";
+  private static final String MESSAGE_ID = "messageId";
+  private static final String PAYLOAD_STRING = "payload";
+  private static final ByteArray PAYLOAD =
+      ByteArray.copyFrom("payload".getBytes(StandardCharsets.UTF_8));
+  private static final Map<String, String> ATTRIBUTES =
+      ImmutableMap.of("key1", "value1", "key2", "value2");
+  private static final Long PUBLISH_TIME = 42L;
+  private static final Message MESSAGE = Message.builder(PAYLOAD)
+      .id(MESSAGE_ID)
+      .attributes(ATTRIBUTES)
+      .publishTime(PUBLISH_TIME)
+      .build();
+  private static final com.google.pubsub.v1.ReceivedMessage RECEIVED_MESSAGE_PB =
+      com.google.pubsub.v1.ReceivedMessage.newBuilder()
+          .setMessage(MESSAGE.toPb())
+          .setAckId(ACK_ID)
+          .build();
+
+  private final PubSub serviceMockReturnsOptions = createStrictMock(PubSub.class);
+  private final PubSubOptions mockOptions = createMock(PubSubOptions.class);
+  private PubSub pubsub;
+  private ReceivedMessage expectedMessage;
+  private ReceivedMessage message;
+
+  private void initializeExpectedMessage(int optionsCalls) {
+    expect(serviceMockReturnsOptions.options()).andReturn(mockOptions).times(optionsCalls);
+    replay(serviceMockReturnsOptions);
+    pubsub = createStrictMock(PubSub.class);
+    expectedMessage =
+        ReceivedMessage.fromPb(serviceMockReturnsOptions, SUBSCRIPTION, RECEIVED_MESSAGE_PB);
+  }
+
+  private void initializeMessage() {
+    message = ReceivedMessage.fromPb(pubsub, SUBSCRIPTION, RECEIVED_MESSAGE_PB);
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    verify(pubsub, serviceMockReturnsOptions);
+  }
+
+  @Test
+  public void testBuilder() {
+    initializeExpectedMessage(3);
+    replay(pubsub);
+    Map<String, String> attributes = ImmutableMap.of("newKey1", "newVal1");
+    ReceivedMessage builtMessage = expectedMessage.toBuilder()
+        .payload("newPayload")
+        .id("newMessageId")
+        .attributes(attributes)
+        .publishTime(PUBLISH_TIME + 1)
+        .build();
+    assertSame(serviceMockReturnsOptions, builtMessage.pubsub());
+    assertEquals(SUBSCRIPTION, builtMessage.subscription());
+    assertEquals(ACK_ID, builtMessage.ackId());
+    assertEquals("newMessageId", builtMessage.id());
+    assertArrayEquals("newPayload".getBytes(Charsets.UTF_8), builtMessage.payload().toByteArray());
+    assertEquals("newPayload", builtMessage.payloadAsString());
+    assertEquals(attributes, builtMessage.attributes());
+    assertEquals(PUBLISH_TIME + 1, (long) builtMessage.publishTime());
+    builtMessage = builtMessage.toBuilder()
+        .payload(PAYLOAD)
+        .id(MESSAGE_ID)
+        .clearAttributes()
+        .addAttribute("key1", "value1")
+        .addAttribute("key2", "value2")
+        .publishTime(PUBLISH_TIME)
+        .build();
+    assertSame(serviceMockReturnsOptions, builtMessage.pubsub());
+    assertEquals(MESSAGE_ID, builtMessage.id());
+    assertEquals(PAYLOAD, builtMessage.payload());
+    assertEquals(PAYLOAD_STRING, builtMessage.payloadAsString());
+    assertEquals(ATTRIBUTES, builtMessage.attributes());
+    assertEquals(PUBLISH_TIME, builtMessage.publishTime());
+    compareReceivedMessage(expectedMessage, builtMessage);
+  }
+
+  @Test
+  public void testToBuilder() {
+    initializeExpectedMessage(2);
+    replay(pubsub);
+    compareReceivedMessage(expectedMessage, expectedMessage.toBuilder().build());
+  }
+
+  @Test
+  public void testAck() {
+    initializeExpectedMessage(1);
+    expect(pubsub.options()).andReturn(mockOptions);
+    pubsub.ack(SUBSCRIPTION, ACK_ID);
+    EasyMock.expectLastCall();
+    replay(pubsub);
+    initializeMessage();
+    message.ack();
+  }
+
+  @Test
+  public void testAckAsync() throws ExecutionException, InterruptedException {
+    initializeExpectedMessage(1);
+    expect(pubsub.options()).andReturn(mockOptions);
+    expect(pubsub.ackAsync(SUBSCRIPTION, ACK_ID)).andReturn(Futures.<Void>immediateFuture(null));
+    EasyMock.expectLastCall();
+    replay(pubsub);
+    initializeMessage();
+    assertNull(message.ackAsync().get());
+  }
+
+  @Test
+  public void testModifyAckDeadline() {
+    initializeExpectedMessage(1);
+    expect(pubsub.options()).andReturn(mockOptions);
+    pubsub.modifyAckDeadline(SUBSCRIPTION, 10, TimeUnit.SECONDS, ACK_ID);
+    EasyMock.expectLastCall();
+    replay(pubsub);
+    initializeMessage();
+    message.modifyAckDeadline(10, TimeUnit.SECONDS);
+  }
+
+  @Test
+  public void testModifyAckDeadlineAsync() throws ExecutionException, InterruptedException {
+    initializeExpectedMessage(1);
+    expect(pubsub.options()).andReturn(mockOptions);
+    expect(pubsub.modifyAckDeadlineAsync(SUBSCRIPTION, 10, TimeUnit.SECONDS, ACK_ID))
+        .andReturn(Futures.<Void>immediateFuture(null));
+    EasyMock.expectLastCall();
+    replay(pubsub);
+    initializeMessage();
+    assertNull(message.modifyAckDeadlineAsync(10, TimeUnit.SECONDS).get());
+  }
+
+  private void compareReceivedMessage(ReceivedMessage expected, ReceivedMessage value) {
+    assertEquals(expected, value);
+    assertEquals(expected.id(), value.id());
+    assertEquals(expected.payload(), value.payload());
+    assertEquals(expected.payloadAsString(), value.payloadAsString());
+    assertEquals(expected.attributes(), value.attributes());
+    assertEquals(expected.publishTime(), value.publishTime());
+    assertEquals(expected.ackId(), value.ackId());
+    assertEquals(expected.subscription(), value.subscription());
+    assertEquals(expected.hashCode(), value.hashCode());
+  }
+}