diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 4b433486f7..2df45f2494 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -180,6 +180,8 @@ Release 0.23.1 - Unreleased
 
     MAPREDUCE-3610. Remove use of the 'dfs.block.size' config for default block size fetching. Use FS#getDefaultBlocksize instead. (Sho Shimauchi via harsh)
 
+    MAPREDUCE-3478. Cannot build against ZooKeeper 3.4.0. (Tom White via mahadev)
+
   OPTIMIZATIONS
 
     MAPREDUCE-3567. Extraneous JobConf objects in AM heap. (Vinod Kumar
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/lib/TestZKClient.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/lib/TestZKClient.java
index 586533ec2a..b857bf309b 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/lib/TestZKClient.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/lib/TestZKClient.java
@@ -29,7 +29,7 @@
 import junit.framework.Assert;
 
 import org.apache.hadoop.yarn.lib.ZKClient;
-import org.apache.zookeeper.server.NIOServerCnxn;
+import org.apache.zookeeper.server.NIOServerCnxnFactory;
 import org.apache.zookeeper.server.ZKDatabase;
 import org.apache.zookeeper.server.ZooKeeperServer;
 import org.apache.zookeeper.server.persistence.FileTxnLog;
@@ -45,7 +45,8 @@ public class TestZKClient  {
 
   protected String hostPort = "127.0.0.1:2000";
   protected int maxCnxns = 0;
-  protected NIOServerCnxn.Factory factory = null;
+  protected NIOServerCnxnFactory factory = null;
+  protected ZooKeeperServer zks;
   protected File tmpDir = null;
 
   public static String send4LetterWord(String host, int port, String cmd)
@@ -144,10 +145,11 @@ public void setUp() throws IOException, InterruptedException {
       BASETEST.mkdirs();
     }
     File dataDir = createTmpDir(BASETEST);
-    ZooKeeperServer zks = new ZooKeeperServer(dataDir, dataDir, 3000);
+    zks = new ZooKeeperServer(dataDir, dataDir, 3000);
     final int PORT = Integer.parseInt(hostPort.split(":")[1]);
     if (factory == null) {
-      factory = new NIOServerCnxn.Factory(new InetSocketAddress(PORT),maxCnxns);
+      factory = new NIOServerCnxnFactory();
+      factory.configure(new InetSocketAddress(PORT), maxCnxns);
     }
     factory.startup(zks);
     Assert.assertTrue("waiting for server up",
@@ -158,8 +160,8 @@ public void setUp() throws IOException, InterruptedException {
   
   @After
   public void tearDown() throws IOException, InterruptedException {
-    if (factory != null) {
-      ZKDatabase zkDb = factory.getZooKeeperServer().getZKDatabase();
+    if (zks != null) {
+      ZKDatabase zkDb = zks.getZKDatabase();
       factory.shutdown();
       try {
         zkDb.close();
diff --git a/hadoop-mapreduce-project/hadoop-yarn/pom.xml b/hadoop-mapreduce-project/hadoop-yarn/pom.xml
index 2c9ab3d970..df178ed197 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/pom.xml
+++ b/hadoop-mapreduce-project/hadoop-yarn/pom.xml
@@ -310,7 +310,7 @@
       <dependency>
         <groupId>org.apache.zookeeper</groupId>
         <artifactId>zookeeper</artifactId>
-        <version>3.3.1</version>
+        <version>3.4.2</version>
         <exclusions>
           <exclusion>
             <!-- otherwise seems to drag in junit 3.8.1 via jline -->