HDFS-9686. Remove useless boxing/unboxing code. Contributed by Kousuke Saruta.

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/servlet/ServerWebApp.java

@@ -36,7 +36,9 @@ import java.text.MessageFormat;
  * and uses its lifecycle to start and stop the server.
  */
 @InterfaceAudience.Private
-public abstract class ServerWebApp extends Server implements ServletContextListener {
+public abstract class ServerWebApp
+       extends Server
+       implements ServletContextListener {
 
   private static final String HOME_DIR = ".home.dir";
   private static final String CONFIG_DIR = ".config.dir";
@@ -61,8 +63,8 @@ public abstract class ServerWebApp extends Server implements ServletContextListe
   /**
    * Constructor for testing purposes.
    */
-  protected ServerWebApp(String name, String homeDir, String configDir, String logDir, String tempDir,
+  protected ServerWebApp(String name, String homeDir, String configDir,
-                         Configuration config) {
+                         String logDir, String tempDir, Configuration config) {
     super(name, homeDir, configDir, logDir, tempDir, config);
   }
 
@@ -120,7 +122,8 @@ public abstract class ServerWebApp extends Server implements ServletContextListe
       String sysProp = name + HOME_DIR;
       homeDir = System.getProperty(sysProp);
       if (homeDir == null) {
-        throw new IllegalArgumentException(MessageFormat.format("System property [{0}] not defined", sysProp));
+        throw new IllegalArgumentException(MessageFormat.format(
+            "System property [{0}] not defined", sysProp));
       }
     }
     return homeDir;
@@ -160,7 +163,8 @@ public abstract class ServerWebApp extends Server implements ServletContextListe
   }
 
   /**
-   * Resolves the host and port InetSocketAddress the web server is listening to.
+   * Resolves the host and port InetSocketAddress the
+   * web server is listening to.
    * <p>
    * This implementation looks for the following 2 properties:
    * <ul>
@@ -168,8 +172,10 @@ public abstract class ServerWebApp extends Server implements ServletContextListe
    *   <li>#SERVER_NAME#.http.port</li>
    * </ul>
    *
-   * @return the host and port InetSocketAddress the web server is listening to.
+   * @return the host and port InetSocketAddress the
-   * @throws ServerException thrown if any of the above 2 properties is not defined.
+   *         web server is listening to.
+   * @throws ServerException thrown
+   *         if any of the above 2 properties is not defined.
    */
   protected InetSocketAddress resolveAuthority() throws ServerException {
     String hostnameKey = getName() + HTTP_HOSTNAME;
@@ -233,6 +239,7 @@ public abstract class ServerWebApp extends Server implements ServletContextListe
    *
    */
   public boolean isSslEnabled() {
-    return Boolean.valueOf(System.getProperty(getName() + SSL_ENABLED, "false"));
+    return Boolean.parseBoolean(
+      System.getProperty(getName() + SSL_ENABLED, "false"));
   }
 }

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -1954,6 +1954,9 @@ Release 2.8.0 - UNRELEASED
 
     HDFS-9726. Refactor IBR code to a new class.  (szetszwo)
 
+    HDFS-9686. Remove useless boxing/unboxing code.
+    (Kousuke Saruta via aajisaka)
+
   BUG FIXES
 
     HDFS-7501. TransactionsSinceLastCheckpoint can be negative on SBNs.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java

@@ -414,7 +414,9 @@ public abstract class FSEditLogOp {
   }
 
   @SuppressWarnings("unchecked")
-  static abstract class AddCloseOp extends FSEditLogOp implements BlockListUpdatingOp {
+  static abstract class AddCloseOp
+         extends FSEditLogOp
+          implements BlockListUpdatingOp {
     int length;
     long inodeId;
     String path;
@@ -635,7 +637,8 @@ public abstract class FSEditLogOp {
             NameNodeLayoutVersion.Feature.BLOCK_STORAGE_POLICY, logVersion)) {
           this.storagePolicyId = FSImageSerialization.readByte(in);
         } else {
-          this.storagePolicyId = HdfsConstants.BLOCK_STORAGE_POLICY_ID_UNSPECIFIED;
+          this.storagePolicyId =
+              HdfsConstants.BLOCK_STORAGE_POLICY_ID_UNSPECIFIED;
         }
         // read clientId and callId
         readRpcIds(in, logVersion);
@@ -715,7 +718,7 @@ public abstract class FSEditLogOp {
           Long.toString(inodeId));
       XMLUtils.addSaxString(contentHandler, "PATH", path);
       XMLUtils.addSaxString(contentHandler, "REPLICATION",
-          Short.valueOf(replication).toString());
+          Short.toString(replication));
       XMLUtils.addSaxString(contentHandler, "MTIME",
           Long.toString(mtime));
       XMLUtils.addSaxString(contentHandler, "ATIME",
@@ -743,7 +746,7 @@ public abstract class FSEditLogOp {
       this.length = Integer.parseInt(st.getValue("LENGTH"));
       this.inodeId = Long.parseLong(st.getValue("INODEID"));
       this.path = st.getValue("PATH");
-      this.replication = Short.valueOf(st.getValue("REPLICATION"));
+      this.replication = Short.parseShort(st.getValue("REPLICATION"));
       this.mtime = Long.parseLong(st.getValue("MTIME"));
       this.atime = Long.parseLong(st.getValue("ATIME"));
       this.blockSize = Long.parseLong(st.getValue("BLOCKSIZE"));
@@ -1184,12 +1187,12 @@ public abstract class FSEditLogOp {
     protected void toXml(ContentHandler contentHandler) throws SAXException {
       XMLUtils.addSaxString(contentHandler, "PATH", path);
       XMLUtils.addSaxString(contentHandler, "REPLICATION",
-          Short.valueOf(replication).toString());
+          Short.toString(replication));
     }
     
     @Override void fromXml(Stanza st) throws InvalidXmlException {
       this.path = st.getValue("PATH");
-      this.replication = Short.valueOf(st.getValue("REPLICATION"));
+      this.replication = Short.parseShort(st.getValue("REPLICATION"));
     }
   }
 
@@ -1977,13 +1980,13 @@ public abstract class FSEditLogOp {
     protected void toXml(ContentHandler contentHandler) throws SAXException {
       XMLUtils.addSaxString(contentHandler, "SRC", src);
       XMLUtils.addSaxString(contentHandler, "MODE",
-          Short.valueOf(permissions.toShort()).toString());
+          Short.toString(permissions.toShort()));
     }
     
     @Override void fromXml(Stanza st) throws InvalidXmlException {
       this.src = st.getValue("SRC");
       this.permissions = new FsPermission(
-          Short.valueOf(st.getValue("MODE")));
+          Short.parseShort(st.getValue("MODE")));
     }
   }
 
@@ -4467,13 +4470,13 @@ public abstract class FSEditLogOp {
     protected void toXml(ContentHandler contentHandler) throws SAXException {
       XMLUtils.addSaxString(contentHandler, "PATH", path);
       XMLUtils.addSaxString(contentHandler, "POLICYID",
-          Byte.valueOf(policyId).toString());
+          Byte.toString(policyId));
     }
 
     @Override
     void fromXml(Stanza st) throws InvalidXmlException {
       this.path = st.getValue("PATH");
-      this.policyId = Byte.valueOf(st.getValue("POLICYID"));
+      this.policyId = Byte.parseByte(st.getValue("POLICYID"));
     }
   }  
 
@@ -4950,7 +4953,8 @@ public abstract class FSEditLogOp {
 
   public static void delegationTokenToXml(ContentHandler contentHandler,
       DelegationTokenIdentifier token) throws SAXException {
-    contentHandler.startElement("", "", "DELEGATION_TOKEN_IDENTIFIER", new AttributesImpl());
+    contentHandler.startElement(
+        "", "", "DELEGATION_TOKEN_IDENTIFIER", new AttributesImpl());
     XMLUtils.addSaxString(contentHandler, "KIND", token.getKind().toString());
     XMLUtils.addSaxString(contentHandler, "SEQUENCE_NUMBER",
         Integer.toString(token.getSequenceNumber()));
@@ -4996,7 +5000,8 @@ public abstract class FSEditLogOp {
 
   public static void delegationKeyToXml(ContentHandler contentHandler,
       DelegationKey key) throws SAXException {
-    contentHandler.startElement("", "", "DELEGATION_KEY", new AttributesImpl());
+    contentHandler.startElement(
+        "", "", "DELEGATION_KEY", new AttributesImpl());
     XMLUtils.addSaxString(contentHandler, "KEY_ID",
         Integer.toString(key.getKeyId()));
     XMLUtils.addSaxString(contentHandler, "EXPIRY_DATE",
@@ -5024,7 +5029,8 @@ public abstract class FSEditLogOp {
 
   public static void permissionStatusToXml(ContentHandler contentHandler,
       PermissionStatus perm) throws SAXException {
-    contentHandler.startElement("", "", "PERMISSION_STATUS", new AttributesImpl());
+    contentHandler.startElement(
+        "", "", "PERMISSION_STATUS", new AttributesImpl());
     XMLUtils.addSaxString(contentHandler, "USERNAME", perm.getUserName());
     XMLUtils.addSaxString(contentHandler, "GROUPNAME", perm.getGroupName());
     fsPermissionToXml(contentHandler, perm.getPermission());
@@ -5042,13 +5048,13 @@ public abstract class FSEditLogOp {
 
   public static void fsPermissionToXml(ContentHandler contentHandler,
       FsPermission mode) throws SAXException {
-    XMLUtils.addSaxString(contentHandler, "MODE", Short.valueOf(mode.toShort())
+    XMLUtils.addSaxString(contentHandler, "MODE",
-        .toString());
+        Short.toString(mode.toShort()));
   }
 
   public static FsPermission fsPermissionFromXml(Stanza st)
       throws InvalidXmlException {
-    short mode = Short.valueOf(st.getValue("MODE"));
+    short mode = Short.parseShort(st.getValue("MODE"));
     return new FsPermission(mode);
   }
 
@@ -5057,7 +5063,8 @@ public abstract class FSEditLogOp {
     XMLUtils.addSaxString(contentHandler, "PERM", v.SYMBOL);
   }
 
-  private static FsAction fsActionFromXml(Stanza st) throws InvalidXmlException {
+  private static FsAction fsActionFromXml(Stanza st)
+      throws InvalidXmlException {
     FsAction v = FSACTION_SYMBOL_MAP.get(st.getValue("PERM"));
     if (v == null)
       throw new InvalidXmlException("Invalid value for FsAction");

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/top/window/RollingWindowManager.java

@@ -173,7 +173,8 @@ public class RollingWindowManager {
    * @param user the user that updated the metric
    * @param delta the amount of change in the metric, e.g., +1
    */
-  public void recordMetric(long time, String command, String user, long delta) {
+  public void recordMetric(long time, String command,
+      String user, long delta) {
     RollingWindow window = getRollingWindow(command, user);
     window.incAt(time, delta);
   }
@@ -208,7 +209,7 @@ public class RollingWindowManager {
       }
       for (int i = 0; i < size; i++) {
         NameValuePair userEntry = reverse.pop();
-        User user = new User(userEntry.name, Long.valueOf(userEntry.value));
+        User user = new User(userEntry.name, userEntry.value);
         op.addUser(user);
       }
     }
@@ -243,7 +244,8 @@ public class RollingWindowManager {
           metricName, userName, windowSum);
       topN.offer(new NameValuePair(userName, windowSum));
     }
-    LOG.debug("topN users size for command {} is: {}", metricName, topN.size());
+    LOG.debug("topN users size for command {} is: {}",
+        metricName, topN.size());
     return topN;
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/ErasureCodeBenchmarkThroughput.java

@@ -69,7 +69,8 @@ import java.util.concurrent.TimeUnit;
  * For example, if the user wants to test reading 1024MB data with 10 clients,
  * he/she should firstly generate 1024MB data with 10 (or more) clients.
  */
-public class ErasureCodeBenchmarkThroughput extends Configured implements Tool {
+public class ErasureCodeBenchmarkThroughput
+       extends Configured implements Tool {
 
   private static final int BUFFER_SIZE_MB = 128;
   private static final String DFS_TMP_DIR = System.getProperty(
@@ -114,13 +115,15 @@ public class ErasureCodeBenchmarkThroughput extends Configured implements Tool {
       System.out.println(msg);
     }
     System.err.println("Usage: ErasureCodeBenchmarkThroughput " +
-        "<read|write|gen|clean> <size in MB> <ec|rep> [num clients] [stf|pos]\n"
+        "<read|write|gen|clean> <size in MB> " +
-        + "Stateful and positional option is only available for read.");
+        "<ec|rep> [num clients] [stf|pos]\n" +
+        "Stateful and positional option is only available for read.");
     System.exit(1);
   }
 
-  private List<Long> doBenchmark(boolean isRead, int dataSizeMB, int numClients,
+  private List<Long> doBenchmark(boolean isRead, int dataSizeMB,
-      boolean isEc, boolean statefulRead, boolean isGen) throws Exception {
+      int numClients, boolean isEc, boolean statefulRead, boolean isGen)
+      throws Exception {
     CompletionService<Long> cs = new ExecutorCompletionService<Long>(
         Executors.newFixedThreadPool(numClients));
     for (int i = 0; i < numClients; i++) {
@@ -217,7 +220,7 @@ public class ErasureCodeBenchmarkThroughput extends Configured implements Tool {
         printUsage("Unknown operation: " + args[0]);
       }
       try {
-        dataSizeMB = Integer.valueOf(args[1]);
+        dataSizeMB = Integer.parseInt(args[1]);
         if (dataSizeMB <= 0) {
           printUsage("Invalid data size: " + dataSizeMB);
         }
@@ -233,7 +236,7 @@ public class ErasureCodeBenchmarkThroughput extends Configured implements Tool {
     }
     if (args.length >= 4 && type != OpType.CLEAN) {
       try {
-        numClients = Integer.valueOf(args[3]);
+        numClients = Integer.parseInt(args[3]);
         if (numClients <= 0) {
           printUsage("Invalid num of clients: " + numClients);
         }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/shortcircuit/TestShortCircuitLocalRead.java

@@ -72,9 +72,9 @@ import org.junit.Test;
 /**
  * Test for short circuit read functionality using {@link BlockReaderLocal}.
  * When a block is being read by a client is on the local datanode, instead of
- * using {@link DataTransferProtocol} and connect to datanode, the short circuit
+ * using {@link DataTransferProtocol} and connect to datanode,
- * read allows reading the file directly from the files on the local file
+ * the short circuit read allows reading the file directly
- * system.
+ * from the files on the local file system.
  */
 public class TestShortCircuitLocalRead {
   private static TemporarySocketDirectory sockDir;
@@ -195,7 +195,8 @@ public class TestShortCircuitLocalRead {
 
     HdfsDataInputStream stm = (HdfsDataInputStream)fs.open(name);
 
-    ByteBuffer actual = ByteBuffer.allocateDirect(expected.length - readOffset);
+    ByteBuffer actual =
+        ByteBuffer.allocateDirect(expected.length - readOffset);
 
     IOUtils.skipFully(stm, readOffset);
 
@@ -230,7 +231,8 @@ public class TestShortCircuitLocalRead {
 
   public void doTestShortCircuitReadLegacy(boolean ignoreChecksum, int size,
       int readOffset, String shortCircuitUser, String readingUser,
-      boolean legacyShortCircuitFails) throws IOException, InterruptedException {
+      boolean legacyShortCircuitFails)
+      throws IOException, InterruptedException {
     doTestShortCircuitReadImpl(ignoreChecksum, size, readOffset,
         shortCircuitUser, readingUser, legacyShortCircuitFails);
   }
@@ -247,7 +249,8 @@ public class TestShortCircuitLocalRead {
    */
   public void doTestShortCircuitReadImpl(boolean ignoreChecksum, int size,
       int readOffset, String shortCircuitUser, String readingUser,
-      boolean legacyShortCircuitFails) throws IOException, InterruptedException {
+      boolean legacyShortCircuitFails)
+      throws IOException, InterruptedException {
     Configuration conf = new Configuration();
     conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.KEY, true);
     conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.SKIP_CHECKSUM_KEY,
@@ -262,7 +265,8 @@ public class TestShortCircuitLocalRead {
     if (shortCircuitUser != null) {
       conf.set(DFSConfigKeys.DFS_BLOCK_LOCAL_PATH_ACCESS_USER_KEY,
           shortCircuitUser);
-      conf.setBoolean(HdfsClientConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL, true);
+      conf.setBoolean(
+          HdfsClientConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL, true);
     }
     if (simulatedStorage) {
       SimulatedFSDataset.setFactory(conf);
@@ -324,7 +328,8 @@ public class TestShortCircuitLocalRead {
    */
   @Test(timeout=60000)
   public void testLocalReadFallback() throws Exception {
-    doTestShortCircuitReadLegacy(true, 13, 0, getCurrentUser(), "notallowed", true);
+    doTestShortCircuitReadLegacy(
+        true, 13, 0, getCurrentUser(), "notallowed", true);
   }
 
   @Test(timeout=60000)
@@ -367,7 +372,8 @@ public class TestShortCircuitLocalRead {
       Token<BlockTokenIdentifier> token = lb.get(0).getBlockToken();
       final DatanodeInfo dnInfo = lb.get(0).getLocations()[0];
       ClientDatanodeProtocol proxy =
-          DFSUtilClient.createClientDatanodeProtocolProxy(dnInfo, conf, 60000, false);
+          DFSUtilClient.createClientDatanodeProtocolProxy(
+              dnInfo, conf, 60000, false);
       try {
         proxy.getBlockLocalPathInfo(blk, token);
         Assert.fail("The call should have failed as this user "
@@ -387,7 +393,8 @@ public class TestShortCircuitLocalRead {
     int size = blockSize;
     Configuration conf = new Configuration();
     conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.KEY, true);
-    conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.SKIP_CHECKSUM_KEY, false);
+    conf.setBoolean(
+        HdfsClientConfigKeys.Read.ShortCircuit.SKIP_CHECKSUM_KEY, false);
     conf.set(DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY,
         new File(sockDir.getDir(),
             "testSkipWithVerifyChecksum._PORT.sock").getAbsolutePath());
@@ -434,7 +441,8 @@ public class TestShortCircuitLocalRead {
     MiniDFSCluster cluster = null;
     HdfsConfiguration conf = new HdfsConfiguration();
     conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.KEY, true);
-    conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.SKIP_CHECKSUM_KEY, false);
+    conf.setBoolean(
+        HdfsClientConfigKeys.Read.ShortCircuit.SKIP_CHECKSUM_KEY, false);
     conf.set(DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY,
         new File(sockDir.getDir(),
             "testHandleTruncatedBlockFile._PORT.sock").getAbsolutePath());
@@ -523,8 +531,8 @@ public class TestShortCircuitLocalRead {
       System.out.println("Usage: test shortcircuit checksum threadCount");
       System.exit(1);
     }
-    boolean shortcircuit = Boolean.valueOf(args[0]);
+    boolean shortcircuit = Boolean.parseBoolean(args[0]);
-    boolean checksum = Boolean.valueOf(args[1]);
+    boolean checksum = Boolean.parseBoolean(args[1]);
     int threadCount = Integer.parseInt(args[2]);
 
     // Setup create a file
@@ -535,7 +543,8 @@ public class TestShortCircuitLocalRead {
     conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.SKIP_CHECKSUM_KEY,
         checksum);
 
-    // Override fileSize and DATA_TO_WRITE to much larger values for benchmark test
+    // Override fileSize and DATA_TO_WRITE to
+    // much larger values for benchmark test
     int fileSize = 1000 * blockSize + 100; // File with 1000 blocks
     final byte [] dataToWrite = AppendTestUtil.randomBytes(seed, fileSize);
 
@@ -557,7 +566,8 @@ public class TestShortCircuitLocalRead {
           for (int i = 0; i < iteration; i++) {
             try {
               String user = getCurrentUser();
-              checkFileContent(fs.getUri(), file1, dataToWrite, 0, user, conf, true);
+              checkFileContent(
+                  fs.getUri(), file1, dataToWrite, 0, user, conf, true);
             } catch (IOException e) {
               e.printStackTrace();
             } catch (InterruptedException e) {
@@ -590,11 +600,13 @@ public class TestShortCircuitLocalRead {
    * through RemoteBlockReader
    * @throws IOException
   */
-  public void doTestShortCircuitReadWithRemoteBlockReader(boolean ignoreChecksum,
+  public void doTestShortCircuitReadWithRemoteBlockReader(
-      int size, String shortCircuitUser, int readOffset,
+      boolean ignoreChecksum, int size, String shortCircuitUser,
-      boolean shortCircuitFails) throws IOException, InterruptedException {
+      int readOffset, boolean shortCircuitFails)
+      throws IOException, InterruptedException {
     Configuration conf = new Configuration();
-    conf.setBoolean(HdfsClientConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADER, true);
+    conf.setBoolean(
+        HdfsClientConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADER, true);
     conf.setBoolean(HdfsClientConfigKeys.Read.ShortCircuit.KEY, true);
 
     MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1)
@@ -603,7 +615,8 @@ public class TestShortCircuitLocalRead {
     // check that / exists
     Path path = new Path("/");
     URI uri = cluster.getURI();
-    assertTrue("/ should be a directory", fs.getFileStatus(path).isDirectory());
+    assertTrue(
+        "/ should be a directory", fs.getFileStatus(path).isDirectory());
 
     byte[] fileData = AppendTestUtil.randomBytes(seed, size);
     Path file1 = new Path("filelocal.dat");
@@ -615,10 +628,12 @@ public class TestShortCircuitLocalRead {
       checkFileContent(uri, file1, fileData, readOffset, shortCircuitUser, 
           conf, shortCircuitFails);
       //RemoteBlockReader have unsupported method read(ByteBuffer bf)
-      assertTrue("RemoteBlockReader unsupported method read(ByteBuffer bf) error",
+      assertTrue(
+          "RemoteBlockReader unsupported method read(ByteBuffer bf) error",
           checkUnsupportedMethod(fs, file1, fileData, readOffset));
     } catch(IOException e) {
-      throw new IOException("doTestShortCircuitReadWithRemoteBlockReader ex error ", e);
+      throw new IOException(
+          "doTestShortCircuitReadWithRemoteBlockReader ex error ", e);
     } catch(InterruptedException inEx) {
       throw inEx;
     } finally {
@@ -630,7 +645,8 @@ public class TestShortCircuitLocalRead {
   private boolean checkUnsupportedMethod(FileSystem fs, Path file,
       byte[] expected, int readOffset) throws IOException {
     HdfsDataInputStream stm = (HdfsDataInputStream)fs.open(file);
-    ByteBuffer actual = ByteBuffer.allocateDirect(expected.length - readOffset);
+    ByteBuffer actual =
+        ByteBuffer.allocateDirect(expected.length - readOffset);
     IOUtils.skipFully(stm, readOffset);
     try {
       stm.read(actual);

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/TestStagingCleanup.java

@@ -245,6 +245,63 @@ import org.junit.Test;
      verify(fs).delete(stagingJobPath, true);
    }
 
+  @Test
+  public void testByPreserveFailedStaging() throws IOException {
+    conf.set(MRJobConfig.MAPREDUCE_JOB_DIR, stagingJobDir);
+    // Failed task's staging files should be kept
+    conf.setBoolean(MRJobConfig.PRESERVE_FAILED_TASK_FILES, true);
+    fs = mock(FileSystem.class);
+    when(fs.delete(any(Path.class), anyBoolean())).thenReturn(true);
+    //Staging Dir exists
+    String user = UserGroupInformation.getCurrentUser().getShortUserName();
+    Path stagingDir = MRApps.getStagingAreaDir(conf, user);
+    when(fs.exists(stagingDir)).thenReturn(true);
+    ApplicationId appId = ApplicationId.newInstance(System.currentTimeMillis(),
+            0);
+    ApplicationAttemptId attemptId = ApplicationAttemptId.newInstance(appId, 1);
+    JobId jobid = recordFactory.newRecordInstance(JobId.class);
+    jobid.setAppId(appId);
+    ContainerAllocator mockAlloc = mock(ContainerAllocator.class);
+    Assert.assertTrue(MRJobConfig.DEFAULT_MR_AM_MAX_ATTEMPTS > 1);
+    MRAppMaster appMaster = new TestMRApp(attemptId, mockAlloc,
+            JobStateInternal.FAILED, MRJobConfig.DEFAULT_MR_AM_MAX_ATTEMPTS);
+    appMaster.init(conf);
+    appMaster.start();
+    appMaster.shutDownJob();
+    //test whether notifyIsLastAMRetry called
+    Assert.assertEquals(true, ((TestMRApp)appMaster).getTestIsLastAMRetry());
+    verify(fs, times(0)).delete(stagingJobPath, true);
+  }
+
+  @Test
+  public void testPreservePatternMatchedStaging() throws IOException {
+    conf.set(MRJobConfig.MAPREDUCE_JOB_DIR, stagingJobDir);
+    // The staging files that are matched to the pattern
+    // should not be deleted
+    conf.set(MRJobConfig.PRESERVE_FILES_PATTERN, "JobDir");
+    fs = mock(FileSystem.class);
+    when(fs.delete(any(Path.class), anyBoolean())).thenReturn(true);
+    //Staging Dir exists
+    String user = UserGroupInformation.getCurrentUser().getShortUserName();
+    Path stagingDir = MRApps.getStagingAreaDir(conf, user);
+    when(fs.exists(stagingDir)).thenReturn(true);
+    ApplicationId appId = ApplicationId.newInstance(System.currentTimeMillis(),
+            0);
+    ApplicationAttemptId attemptId = ApplicationAttemptId.newInstance(appId, 1);
+    JobId jobid = recordFactory.newRecordInstance(JobId.class);
+    jobid.setAppId(appId);
+    ContainerAllocator mockAlloc = mock(ContainerAllocator.class);
+    Assert.assertTrue(MRJobConfig.DEFAULT_MR_AM_MAX_ATTEMPTS > 1);
+    MRAppMaster appMaster = new TestMRApp(attemptId, mockAlloc,
+            JobStateInternal.RUNNING, MRJobConfig.DEFAULT_MR_AM_MAX_ATTEMPTS);
+    appMaster.init(conf);
+    appMaster.start();
+    appMaster.shutDownJob();
+    //test whether notifyIsLastAMRetry called
+    Assert.assertEquals(true, ((TestMRApp)appMaster).getTestIsLastAMRetry());
+    verify(fs, times(0)).delete(stagingJobPath, true);
+  }
+
    private class TestMRApp extends MRAppMaster {
      ContainerAllocator allocator;
      boolean testIsLastAMRetry = false;