HDFS-6124. Add final modifier to class members. (Contributed by Suresh Srinivas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1581124 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -438,6 +438,9 @@ Release 2.4.0 - UNRELEASED
 
     HDFS-5138. Support HDFS upgrade in HA. (atm via todd)
 
+    HDFS-6124. Add final modifier to class members. (Suresh Srinivas via
+    Arpit Agarwal)
+
   OPTIMIZATIONS
 
     HDFS-5790. LeaseManager.findPath is very slow when many leases need recovery

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockMissingException.java

@@ -33,8 +33,8 @@ public class BlockMissingException extends IOException {
 
   private static final long serialVersionUID = 1L;
 
-  private String filename;
-  private long   offset;
+  private final String filename;
+  private final long   offset;
 
   /**
    * An exception that indicates that file was corrupted.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReaderLocal.java

@@ -56,10 +56,10 @@ import com.google.common.base.Preconditions;
 class BlockReaderLocal implements BlockReader {
   static final Log LOG = LogFactory.getLog(BlockReaderLocal.class);
 
-  private static DirectBufferPool bufferPool = new DirectBufferPool();
+  private static final DirectBufferPool bufferPool = new DirectBufferPool();
 
   public static class Builder {
-    private int bufferSize;
+    private final int bufferSize;
     private boolean verifyChecksum;
     private int maxReadahead;
     private String filename;
@@ -160,12 +160,12 @@ class BlockReaderLocal implements BlockReader {
   /**
    * Cache of Checksum#bytesPerChecksum.
    */
-  private int bytesPerChecksum;
+  private final int bytesPerChecksum;
 
   /**
    * Cache of Checksum#checksumSize.
    */
-  private int checksumSize;
+  private final int checksumSize;
 
   /**
    * Maximum number of chunks to allocate.
@@ -191,7 +191,7 @@ class BlockReaderLocal implements BlockReader {
    * The rationale is that allocating a lot of buffers of different sizes would
    * make it very difficult for the DirectBufferPool to re-use buffers. 
    */
-  private int maxReadaheadLength;
+  private final int maxReadaheadLength;
 
   /**
    * Buffers data starting at the current dataPos and extending on

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReaderLocalLegacy.java

@@ -137,7 +137,7 @@ class BlockReaderLocalLegacy implements BlockReader {
   
   // Multiple datanodes could be running on the local machine. Store proxies in
   // a map keyed by the ipc port of the datanode.
-  private static Map<Integer, LocalDatanodeInfo> localDatanodeInfoMap = new HashMap<Integer, LocalDatanodeInfo>();
+  private static final Map<Integer, LocalDatanodeInfo> localDatanodeInfoMap = new HashMap<Integer, LocalDatanodeInfo>();
 
   private final FileInputStream dataIn; // reader for the data file
   private final FileInputStream checksumIn;   // reader for the checksum file
@@ -162,7 +162,7 @@ class BlockReaderLocalLegacy implements BlockReader {
   private DataChecksum checksum;
   private final boolean verifyChecksum;
 
-  private static DirectBufferPool bufferPool = new DirectBufferPool();
+  private static final DirectBufferPool bufferPool = new DirectBufferPool();
 
   private final int bytesPerChecksum;
   private final int checksumSize;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/CorruptFileBlockIterator.java

@@ -31,7 +31,7 @@ import org.apache.hadoop.fs.RemoteIterator;
  */
 public class CorruptFileBlockIterator implements RemoteIterator<Path> {
   private final DFSClient dfs;
-  private String path;
+  private final String path;
 
   private String[] files = null;
   private int fileIdx = 0;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -221,18 +221,18 @@ public class DFSClient implements java.io.Closeable, RemotePeerFactory {
   private volatile FsServerDefaults serverDefaults;
   private volatile long serverDefaultsLastUpdate;
   final String clientName;
-  SocketFactory socketFactory;
+  final SocketFactory socketFactory;
   final ReplaceDatanodeOnFailure dtpReplaceDatanodeOnFailure;
   final FileSystem.Statistics stats;
   private final String authority;
-  private Random r = new Random();
+  private final Random r = new Random();
   private SocketAddress[] localInterfaceAddrs;
   private DataEncryptionKey encryptionKey;
   private final CachingStrategy defaultReadCachingStrategy;
   private final CachingStrategy defaultWriteCachingStrategy;
   private final ClientContext clientContext;
   private volatile long hedgedReadThresholdMillis;
-  private static DFSHedgedReadMetrics HEDGED_READ_METRIC =
+  private static final DFSHedgedReadMetrics HEDGED_READ_METRIC =
       new DFSHedgedReadMetrics();
   private static ThreadPoolExecutor HEDGED_READ_THREAD_POOL;
   
@@ -962,7 +962,7 @@ public class DFSClient implements java.io.Closeable, RemotePeerFactory {
     }
   }
   
-  private static Map<String, Boolean> localAddrMap = Collections
+  private static final Map<String, Boolean> localAddrMap = Collections
       .synchronizedMap(new HashMap<String, Boolean>());
   
   static boolean isLocalAddress(InetSocketAddress targetAddr) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSHedgedReadMetrics.java

@@ -25,9 +25,9 @@ import java.util.concurrent.atomic.AtomicLong;
  * we can grab them from client side, like HBase.
  */
 public class DFSHedgedReadMetrics {
-  public AtomicLong hedgedReadOps = new AtomicLong();
-  public AtomicLong hedgedReadOpsWin = new AtomicLong();
-  public AtomicLong hedgedReadOpsInCurThread = new AtomicLong();
+  public final AtomicLong hedgedReadOps = new AtomicLong();
+  public final AtomicLong hedgedReadOpsWin = new AtomicLong();
+  public final AtomicLong hedgedReadOpsInCurThread = new AtomicLong();
 
   public void incHedgedReadOps() {
     hedgedReadOps.incrementAndGet();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java

@@ -1508,8 +1508,8 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
 
   /** Utility class to encapsulate data node info and its address. */
   static class DNAddrPair {
-    DatanodeInfo info;
-    InetSocketAddress addr;
+    final DatanodeInfo info;
+    final InetSocketAddress addr;
     DNAddrPair(DatanodeInfo info, InetSocketAddress addr) {
       this.info = info;
       this.addr = addr;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java

@@ -148,20 +148,20 @@ public class DFSOutputStream extends FSOutputSummer
   private final AtomicBoolean persistBlocks = new AtomicBoolean(false);
   private volatile boolean appendChunk = false;   // appending to existing partial block
   private long initialFileSize = 0; // at time of file open
-  private Progressable progress;
+  private final Progressable progress;
   private final short blockReplication; // replication factor of file
   private boolean shouldSyncBlock = false; // force blocks to disk upon close
-  private AtomicReference<CachingStrategy> cachingStrategy;
+  private final AtomicReference<CachingStrategy> cachingStrategy;
   private boolean failPacket = false;
   
   private static class Packet {
     private static final long HEART_BEAT_SEQNO = -1L;
-    long seqno; // sequencenumber of buffer in block
+    final long seqno; // sequencenumber of buffer in block
     final long offsetInBlock; // offset in block
     boolean syncBlock; // this packet forces the current block to disk
     int numChunks; // number of chunks currently in packet
     final int maxChunks; // max chunks in packet
-    byte[]  buf;
+    final byte[]  buf;
     private boolean lastPacketInBlock; // is this the last packet in block?
 
     /**
@@ -314,7 +314,7 @@ public class DFSOutputStream extends FSOutputSummer
     private ResponseProcessor response = null;
     private volatile DatanodeInfo[] nodes = null; // list of targets for current block
     private volatile String[] storageIDs = null;
-    private LoadingCache<DatanodeInfo, DatanodeInfo> excludedNodes =
+    private final LoadingCache<DatanodeInfo, DatanodeInfo> excludedNodes =
         CacheBuilder.newBuilder()
         .expireAfterWrite(
             dfsClient.getConf().excludedNodesCacheExpiry,

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java

@@ -183,7 +183,7 @@ public class DFSUtil {
    */ 
   @InterfaceAudience.Private 
   public static class DecomStaleComparator implements Comparator<DatanodeInfo> {
-    private long staleInterval;
+    private final long staleInterval;
 
     /**
      * Constructor of DecomStaleComparator
@@ -1416,8 +1416,8 @@ public class DFSUtil {
     }
   }
   
-  public static Options helpOptions = new Options();
-  public static Option helpOpt = new Option("h", "help", false,
+  public static final Options helpOptions = new Options();
+  public static final Option helpOpt = new Option("h", "help", false,
       "get help information");
 
   static {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DomainSocketFactory.java

@@ -86,7 +86,7 @@ class DomainSocketFactory {
   /**
    * Information about domain socket paths.
    */
-  Cache<String, PathState> pathMap =
+  final Cache<String, PathState> pathMap =
       CacheBuilder.newBuilder()
       .expireAfterWrite(10, TimeUnit.MINUTES)
       .build();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/RemoteBlockReader2.java

@@ -91,7 +91,7 @@ public class RemoteBlockReader2  implements BlockReader {
   private final ReadableByteChannel in;
   private DataChecksum checksum;
   
-  private PacketReceiver packetReceiver = new PacketReceiver(true);
+  private final PacketReceiver packetReceiver = new PacketReceiver(true);
   private ByteBuffer curDataSlice = null;
 
   /** offset in block of the last chunk received */

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/StorageType.java

@@ -31,5 +31,5 @@ public enum StorageType {
   DISK,
   SSD;
 
-  public static StorageType DEFAULT = DISK;
+  public static final StorageType DEFAULT = DISK;
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/client/ShortCircuitCache.java

@@ -289,7 +289,7 @@ public class ShortCircuitCache implements Closeable {
    * Maximum total size of the cache, including both mmapped and
    * no$-mmapped elements.
    */
-  private int maxTotalSize;
+  private final int maxTotalSize;
 
   /**
    * Non-mmaped elements older than this will be closed.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/DomainPeerServer.java

@@ -30,7 +30,7 @@ import org.apache.hadoop.classification.InterfaceAudience;
 
 @InterfaceAudience.Private
 public class DomainPeerServer implements PeerServer {
-  static Log LOG = LogFactory.getLog(DomainPeerServer.class);
+  static final Log LOG = LogFactory.getLog(DomainPeerServer.class);
   private final DomainSocket sock;
 
   DomainPeerServer(DomainSocket sock) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/TcpPeerServer.java

@@ -35,7 +35,7 @@ import org.apache.hadoop.ipc.Server;
 
 @InterfaceAudience.Private
 public class TcpPeerServer implements PeerServer {
-  static Log LOG = LogFactory.getLog(TcpPeerServer.class);
+  static final Log LOG = LogFactory.getLog(TcpPeerServer.class);
 
   private final ServerSocket serverSocket;
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/BlockListAsLongs.java

@@ -77,7 +77,7 @@ public class BlockListAsLongs implements Iterable<Block> {
             + (blockIndex - finalizedSize) * LONGS_PER_UC_BLOCK;
   }
 
-  private long[] blockList;
+  private final long[] blockList;
   
   /**
    * Create block report from finalized and under construction lists of blocks.
@@ -141,7 +141,7 @@ public class BlockListAsLongs implements Iterable<Block> {
   @InterfaceStability.Evolving
   public class BlockReportIterator implements Iterator<Block> {
     private int currentBlockIndex;
-    private Block block;
+    private final Block block;
     private ReplicaState currentReplicaState;
 
     BlockReportIterator() {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/BlockLocalPathInfo.java

@@ -27,7 +27,7 @@ import org.apache.hadoop.classification.InterfaceStability;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class BlockLocalPathInfo {
-  private ExtendedBlock block;
+  private final ExtendedBlock block;
   private String localBlockPath = "";  // local file storing the data
   private String localMetaPath = "";   // local file storing the checksum
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/CorruptFileBlocks.java

@@ -28,8 +28,8 @@ public class CorruptFileBlocks {
   // used for hashCode
   private static final int PRIME = 16777619;
 
-  private String[] files;
-  private String cookie;
+  private final String[] files;
+  private final String cookie;
 
   public CorruptFileBlocks() {
     this(new String[0], "");

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/DatanodeLocalInfo.java

@@ -27,9 +27,9 @@ import org.apache.hadoop.classification.InterfaceStability;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class DatanodeLocalInfo {
-  private String softwareVersion;
-  private String configVersion;
-  private long uptime; // datanode uptime in seconds.
+  private final String softwareVersion;
+  private final String configVersion;
+  private final long uptime; // datanode uptime in seconds.
 
   public DatanodeLocalInfo(String softwareVersion,
       String configVersion, long uptime) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/HdfsConstants.java

@@ -48,7 +48,7 @@ public class HdfsConstants {
       "org.apache.hadoop.hdfs.protocol.ClientDatanodeProtocol";
   
   
-  public static int MIN_BLOCKS_FOR_WRITE = 5;
+  public static final int MIN_BLOCKS_FOR_WRITE = 5;
 
   // Long that indicates "leave current quota unchanged"
   public static final long QUOTA_DONT_SET = Long.MAX_VALUE;
@@ -65,8 +65,8 @@ public class HdfsConstants {
   // HADOOP-438
   // Currently we set the maximum length to 8k characters and the maximum depth
   // to 1k.
-  public static int MAX_PATH_LENGTH = 8000;
-  public static int MAX_PATH_DEPTH = 1000;
+  public static final int MAX_PATH_LENGTH = 8000;
+  public static final int MAX_PATH_DEPTH = 1000;
 
   // TODO should be conf injected?
   public static final int DEFAULT_DATA_SOCKET_SIZE = 128 * 1024;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/HdfsFileStatus.java

@@ -32,21 +32,21 @@ import org.apache.hadoop.hdfs.DFSUtil;
 @InterfaceStability.Evolving
 public class HdfsFileStatus {
 
-  private byte[] path;  // local name of the inode that's encoded in java UTF8
-  private byte[] symlink; // symlink target encoded in java UTF8 or null
-  private long length;
-  private boolean isdir;
-  private short block_replication;
-  private long blocksize;
-  private long modification_time;
-  private long access_time;
-  private FsPermission permission;
-  private String owner;
-  private String group;
-  private long fileId;
+  private final byte[] path;  // local name of the inode that's encoded in java UTF8
+  private final byte[] symlink; // symlink target encoded in java UTF8 or null
+  private final long length;
+  private final boolean isdir;
+  private final short block_replication;
+  private final long blocksize;
+  private final long modification_time;
+  private final long access_time;
+  private final FsPermission permission;
+  private final String owner;
+  private final String group;
+  private final long fileId;
   
   // Used by dir, not including dot and dotdot. Always zero for a regular file.
-  private int childrenNum;
+  private final int childrenNum;
   
   public static final byte[] EMPTY_NAME = new byte[0];
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/HdfsLocatedFileStatus.java

@@ -33,7 +33,7 @@ import org.apache.hadoop.hdfs.DFSUtil;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class HdfsLocatedFileStatus extends HdfsFileStatus {
-  private LocatedBlocks locations;
+  private final LocatedBlocks locations;
   
   /**
    * Constructor

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/LocatedBlock.java

@@ -39,13 +39,13 @@ import com.google.common.collect.Lists;
 @InterfaceStability.Evolving
 public class LocatedBlock {
 
-  private ExtendedBlock b;
+  private final ExtendedBlock b;
   private long offset;  // offset of the first byte of the block in the file
-  private DatanodeInfo[] locs;
+  private final DatanodeInfo[] locs;
   /** Storage ID for each replica */
-  private String[] storageIDs;
+  private final String[] storageIDs;
   // Storage type for each replica, if reported.
-  private StorageType[] storageTypes;
+  private final StorageType[] storageTypes;
   // corrupt flag is true if all of the replicas of a block are corrupt.
   // else false. If block has few corrupt replicas, they are filtered and 
   // their locations are not part of this object

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/LocatedBlocks.java

@@ -30,9 +30,9 @@ import org.apache.hadoop.classification.InterfaceStability;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class LocatedBlocks {
-  private long fileLength;
-  private List<LocatedBlock> blocks; // array of blocks with prioritized locations
-  private boolean underConstruction;
+  private final long fileLength;
+  private final List<LocatedBlock> blocks; // array of blocks with prioritized locations
+  private final boolean underConstruction;
   private LocatedBlock lastLocatedBlock = null;
   private boolean isLastBlockComplete = false;
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/RollingUpgradeStatus.java

@@ -26,7 +26,7 @@ import org.apache.hadoop.classification.InterfaceStability;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class RollingUpgradeStatus {
-  private String blockPoolId;
+  private final String blockPoolId;
 
   public RollingUpgradeStatus(String blockPoolId) {
     this.blockPoolId = blockPoolId;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/SnapshotDiffReport.java

@@ -47,7 +47,7 @@ public class SnapshotDiffReport {
     DELETE("-"), 
     RENAME("R");
     
-    private String label;
+    private final String label;
     
     private DiffType(String label) {
       this.label = label;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/SnapshottableDirectoryStatus.java

@@ -44,16 +44,16 @@ public class SnapshottableDirectoryStatus {
   };
 
   /** Basic information of the snapshottable directory */
-  private HdfsFileStatus dirStatus;
+  private final HdfsFileStatus dirStatus;
   
   /** Number of snapshots that have been taken*/
-  private int snapshotNumber;
+  private final int snapshotNumber;
   
   /** Number of snapshots allowed. */
-  private int snapshotQuota;
+  private final int snapshotQuota;
   
   /** Full path of the parent. */
-  private byte[] parentFullPath;
+  private final byte[] parentFullPath;
   
   public SnapshottableDirectoryStatus(long modification_time, long access_time,
       FsPermission permission, String owner, String group, byte[] localName,

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/datatransfer/DataTransferEncryptor.java

@@ -299,7 +299,7 @@ public class DataTransferEncryptor {
    */
   private static class SaslServerCallbackHandler implements CallbackHandler {
     
-    private BlockPoolTokenSecretManager blockPoolTokenSecretManager;
+    private final BlockPoolTokenSecretManager blockPoolTokenSecretManager;
     
     public SaslServerCallbackHandler(BlockPoolTokenSecretManager
         blockPoolTokenSecretManager) {
@@ -347,8 +347,8 @@ public class DataTransferEncryptor {
    */
   private static class SaslClientCallbackHandler implements CallbackHandler {
     
-    private byte[] encryptionKey;
-    private String userName;
+    private final byte[] encryptionKey;
+    private final String userName;
     
     public SaslClientCallbackHandler(byte[] encryptionKey, String userName) {
       this.encryptionKey = encryptionKey;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/datatransfer/PacketReceiver.java

@@ -47,7 +47,7 @@ public class PacketReceiver implements Closeable {
    */
   private static final int MAX_PACKET_SIZE = 16 * 1024 * 1024;
 
-  static Log LOG = LogFactory.getLog(PacketReceiver.class);
+  static final Log LOG = LogFactory.getLog(PacketReceiver.class);
   
   private static final DirectBufferPool bufferPool = new DirectBufferPool();
   private final boolean useDirectBuffers;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolTranslatorPB.java

@@ -1078,7 +1078,7 @@ public class ClientNamenodeProtocolTranslatorPB implements
 
   private static class BatchedCacheEntries
       implements BatchedEntries<CacheDirectiveEntry> {
-    private ListCacheDirectivesResponseProto response;
+    private final ListCacheDirectivesResponseProto response;
 
     BatchedCacheEntries(
         ListCacheDirectivesResponseProto response) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/client/IPCLoggerChannel.java

@@ -133,7 +133,7 @@ public class IPCLoggerChannel implements AsyncLogger {
   /**
    * Stopwatch which starts counting on each heartbeat that is sent
    */
-  private Stopwatch lastHeartbeatStopwatch = new Stopwatch();
+  private final Stopwatch lastHeartbeatStopwatch = new Stopwatch();
   
   private static final long HEARTBEAT_INTERVAL_MILLIS = 1000;
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/protocol/RequestInfo.java

@@ -22,10 +22,10 @@ import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 
 @InterfaceAudience.Private
 public class RequestInfo {
-  private String jid;
+  private final String jid;
   private long epoch;
   private long ipcSerialNumber;
-  private long committedTxId;
+  private final long committedTxId;
   
   public RequestInfo(String jid, long epoch, long ipcSerialNumber,
       long committedTxId) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalMetrics.java

@@ -52,7 +52,7 @@ class JournalMetrics {
       60*60 // 1h
   };
   
-  MutableQuantiles[] syncsQuantiles;
+  final MutableQuantiles[] syncsQuantiles;
   
   private final Journal journal;
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalNode.java

@@ -63,7 +63,7 @@ public class JournalNode implements Tool, Configurable, JournalNodeMXBean {
   private Configuration conf;
   private JournalNodeRpcServer rpcServer;
   private JournalNodeHttpServer httpServer;
-  private Map<String, Journal> journalsById = Maps.newHashMap();
+  private final Map<String, Journal> journalsById = Maps.newHashMap();
   private ObjectName journalNodeInfoBeanName;
   private String httpServerURI;
   private File localDir;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalNodeHttpServer.java

@@ -39,7 +39,7 @@ public class JournalNodeHttpServer {
   public static final String JN_ATTRIBUTE_KEY = "localjournal";
 
   private HttpServer2 httpServer;
-  private JournalNode localJournalNode;
+  private final JournalNode localJournalNode;
 
   private final Configuration conf;
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalNodeRpcServer.java

@@ -50,7 +50,7 @@ import com.google.protobuf.BlockingService;
 class JournalNodeRpcServer implements QJournalProtocol {
 
   private static final int HANDLER_COUNT = 5;
-  private JournalNode jn;
+  private final JournalNode jn;
   private Server server;
 
   JournalNodeRpcServer(Configuration conf, JournalNode jn) throws IOException {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/security/token/block/BlockTokenIdentifier.java

@@ -40,7 +40,7 @@ public class BlockTokenIdentifier extends TokenIdentifier {
   private String userId;
   private String blockPoolId;
   private long blockId;
-  private EnumSet<AccessMode> modes;
+  private final EnumSet<AccessMode> modes;
 
   private byte [] cache;
   

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/security/token/block/BlockTokenSecretManager.java

@@ -74,11 +74,11 @@ public class BlockTokenSecretManager extends
   private int serialNo;
   private BlockKey currentKey;
   private BlockKey nextKey;
-  private Map<Integer, BlockKey> allKeys;
+  private final Map<Integer, BlockKey> allKeys;
   private String blockPoolId;
-  private String encryptionAlgorithm;
+  private final String encryptionAlgorithm;
   
-  private SecureRandom nonceGenerator = new SecureRandom();
+  private final SecureRandom nonceGenerator = new SecureRandom();
 
   public static enum AccessMode {
     READ, WRITE, COPY, REPLACE

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/security/token/block/ExportedBlockKeys.java

@@ -36,7 +36,7 @@ public class ExportedBlockKeys implements Writable {
   private boolean isBlockTokenEnabled;
   private long keyUpdateInterval;
   private long tokenLifetime;
-  private BlockKey currentKey;
+  private final BlockKey currentKey;
   private BlockKey[] allKeys;
 
   public ExportedBlockKeys() {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java

@@ -203,23 +203,23 @@ public class Balancer {
   private final double threshold;
   
   // all data node lists
-  private Collection<Source> overUtilizedDatanodes
+  private final Collection<Source> overUtilizedDatanodes
                                = new LinkedList<Source>();
-  private Collection<Source> aboveAvgUtilizedDatanodes
+  private final Collection<Source> aboveAvgUtilizedDatanodes
                                = new LinkedList<Source>();
-  private Collection<BalancerDatanode> belowAvgUtilizedDatanodes
+  private final Collection<BalancerDatanode> belowAvgUtilizedDatanodes
                                = new LinkedList<BalancerDatanode>();
-  private Collection<BalancerDatanode> underUtilizedDatanodes
+  private final Collection<BalancerDatanode> underUtilizedDatanodes
                                = new LinkedList<BalancerDatanode>();
   
-  private Collection<Source> sources
+  private final Collection<Source> sources
                                = new HashSet<Source>();
-  private Collection<BalancerDatanode> targets
+  private final Collection<BalancerDatanode> targets
                                = new HashSet<BalancerDatanode>();
   
-  private Map<Block, BalancerBlock> globalBlockList
+  private final Map<Block, BalancerBlock> globalBlockList
                  = new HashMap<Block, BalancerBlock>();
-  private MovedBlocks movedBlocks = new MovedBlocks();
+  private final MovedBlocks movedBlocks = new MovedBlocks();
   /** Map (datanodeUuid -> BalancerDatanodes) */
   private final Map<String, BalancerDatanode> datanodeMap
       = new HashMap<String, BalancerDatanode>();
@@ -421,8 +421,8 @@ public class Balancer {
   
   /* A class for keeping track of blocks in the Balancer */
   static private class BalancerBlock {
-    private Block block; // the block
-    private List<BalancerDatanode> locations
+    private final Block block; // the block
+    private final List<BalancerDatanode> locations
             = new ArrayList<BalancerDatanode>(3); // its locations
     
     /* Constructor */
@@ -469,7 +469,7 @@ public class Balancer {
    * An object of this class is stored in a source node. 
    */
   static private class NodeTask {
-    private BalancerDatanode datanode; //target node
+    private final BalancerDatanode datanode; //target node
     private long size;  //bytes scheduled to move
     
     /* constructor */
@@ -498,7 +498,7 @@ public class Balancer {
     final long maxSize2Move;
     private long scheduledSize = 0L;
     //  blocks being moved but not confirmed yet
-    private List<PendingBlockMove> pendingBlocks = 
+    private final List<PendingBlockMove> pendingBlocks =
       new ArrayList<PendingBlockMove>(MAX_NUM_CONCURRENT_MOVES); 
     
     @Override
@@ -615,13 +615,13 @@ public class Balancer {
       }
     }
     
-    private ArrayList<NodeTask> nodeTasks = new ArrayList<NodeTask>(2);
+    private final ArrayList<NodeTask> nodeTasks = new ArrayList<NodeTask>(2);
     private long blocksToReceive = 0L;
     /* source blocks point to balancerBlocks in the global list because
      * we want to keep one copy of a block in balancer and be aware that
      * the locations are changing over time.
      */
-    private List<BalancerBlock> srcBlockList
+    private final List<BalancerBlock> srcBlockList
             = new ArrayList<BalancerBlock>();
     
     /* constructor */
@@ -1092,7 +1092,7 @@ public class Balancer {
       return bytesMoved;
     }
   };
-  private BytesMoved bytesMoved = new BytesMoved();
+  private final BytesMoved bytesMoved = new BytesMoved();
   
   /* Start a thread to dispatch block moves for each source. 
    * The thread selects blocks to move & sends request to proxy source to

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/BalancingPolicy.java

@@ -75,7 +75,7 @@ abstract class BalancingPolicy {
    * Cluster is balanced if each node is balanced.
    */
   static class Node extends BalancingPolicy {
-    static Node INSTANCE = new Node();
+    static final Node INSTANCE = new Node();
     private Node() {}
 
     @Override
@@ -99,7 +99,7 @@ abstract class BalancingPolicy {
    * Cluster is balanced if each pool in each node is balanced.
    */
   static class Pool extends BalancingPolicy {
-    static Pool INSTANCE = new Pool();
+    static final Pool INSTANCE = new Pool();
     private Pool() {}
 
     @Override

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java

@@ -116,8 +116,8 @@ public class BlockManager {
   private volatile long corruptReplicaBlocksCount = 0L;
   private volatile long underReplicatedBlocksCount = 0L;
   private volatile long scheduledReplicationBlocksCount = 0L;
-  private AtomicLong excessBlocksCount = new AtomicLong(0L);
-  private AtomicLong postponedMisreplicatedBlocksCount = new AtomicLong(0L);
+  private final AtomicLong excessBlocksCount = new AtomicLong(0L);
+  private final AtomicLong postponedMisreplicatedBlocksCount = new AtomicLong(0L);
   
   /** Used by metrics */
   public long getPendingReplicationBlocksCount() {
@@ -3416,16 +3416,16 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
 
   private static class ReplicationWork {
 
-    private Block block;
-    private BlockCollection bc;
+    private final Block block;
+    private final BlockCollection bc;
 
-    private DatanodeDescriptor srcNode;
-    private List<DatanodeDescriptor> containingNodes;
-    private List<DatanodeStorageInfo> liveReplicaStorages;
-    private int additionalReplRequired;
+    private final DatanodeDescriptor srcNode;
+    private final List<DatanodeDescriptor> containingNodes;
+    private final List<DatanodeStorageInfo> liveReplicaStorages;
+    private final int additionalReplRequired;
 
     private DatanodeStorageInfo targets[];
-    private int priority;
+    private final int priority;
 
     public ReplicationWork(Block block,
         BlockCollection bc,

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlocksMap.java

@@ -35,7 +35,7 @@ import com.google.common.collect.Iterables;
  */
 class BlocksMap {
   private static class StorageIterator implements Iterator<DatanodeStorageInfo> {
-    private BlockInfo blockInfo;
+    private final BlockInfo blockInfo;
     private int nextIdx = 0;
       
     StorageIterator(BlockInfo blkInfo) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/CorruptReplicasMap.java

@@ -46,7 +46,7 @@ public class CorruptReplicasMap{
     CORRUPTION_REPORTED  // client or datanode reported the corruption
   }
 
-  private SortedMap<Block, Map<DatanodeDescriptor, Reason>> corruptReplicasMap =
+  private final SortedMap<Block, Map<DatanodeDescriptor, Reason>> corruptReplicasMap =
     new TreeMap<Block, Map<DatanodeDescriptor, Reason>>();
   
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java

@@ -55,7 +55,7 @@ public class DatanodeDescriptor extends DatanodeInfo {
 
   // Stores status of decommissioning.
   // If node is not decommissioning, do not use this object for anything.
-  public DecommissioningStatus decommissioningStatus = new DecommissioningStatus();
+  public final DecommissioningStatus decommissioningStatus = new DecommissioningStatus();
   
   /** Block and targets pair */
   @InterfaceAudience.Private
@@ -190,12 +190,12 @@ public class DatanodeDescriptor extends DatanodeInfo {
   private long bandwidth;
 
   /** A queue of blocks to be replicated by this datanode */
-  private BlockQueue<BlockTargetPair> replicateBlocks = new BlockQueue<BlockTargetPair>();
+  private final BlockQueue<BlockTargetPair> replicateBlocks = new BlockQueue<BlockTargetPair>();
   /** A queue of blocks to be recovered by this datanode */
-  private BlockQueue<BlockInfoUnderConstruction> recoverBlocks =
+  private final BlockQueue<BlockInfoUnderConstruction> recoverBlocks =
                                 new BlockQueue<BlockInfoUnderConstruction>();
   /** A set of blocks to be invalidated by this datanode */
-  private LightWeightHashSet<Block> invalidateBlocks = new LightWeightHashSet<Block>();
+  private final LightWeightHashSet<Block> invalidateBlocks = new LightWeightHashSet<Block>();
 
   /* Variables for maintaining number of blocks scheduled to be written to
    * this storage. This count is approximate and might be slightly bigger

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/Host2NodesMap.java

@@ -31,9 +31,9 @@ import org.apache.hadoop.hdfs.DFSUtil;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 class Host2NodesMap {
-  private HashMap<String, DatanodeDescriptor[]> map
+  private final HashMap<String, DatanodeDescriptor[]> map
     = new HashMap<String, DatanodeDescriptor[]>();
-  private ReadWriteLock hostmapLock = new ReentrantReadWriteLock();
+  private final ReadWriteLock hostmapLock = new ReentrantReadWriteLock();
 
   /** Check if node is already in the map. */
   boolean contains(DatanodeDescriptor node) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingDataNodeMessages.java

@@ -34,7 +34,7 @@ import com.google.common.collect.Maps;
  * */  
 class PendingDataNodeMessages {
   
-  Map<Block, Queue<ReportedBlockInfo>> queueByBlockId =
+  final Map<Block, Queue<ReportedBlockInfo>> queueByBlockId =
     Maps.newHashMap();
   private int count = 0;
   

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingReplicationBlocks.java

@@ -46,8 +46,8 @@ import org.apache.hadoop.util.Daemon;
 class PendingReplicationBlocks {
   private static final Log LOG = BlockManager.LOG;
 
-  private Map<Block, PendingBlockInfo> pendingReplications;
-  private ArrayList<Block> timedOutItems;
+  private final Map<Block, PendingBlockInfo> pendingReplications;
+  private final ArrayList<Block> timedOutItems;
   Daemon timerThread = null;
   private volatile boolean fsRunning = true;
 
@@ -56,7 +56,7 @@ class PendingReplicationBlocks {
   // a request is timed out.
   //
   private long timeout = 5 * 60 * 1000;
-  private long defaultRecheckInterval = 5 * 60 * 1000;
+  private final static long DEFAULT_RECHECK_INTERVAL = 5 * 60 * 1000;
 
   PendingReplicationBlocks(long timeoutPeriod) {
     if ( timeoutPeriod > 0 ) {
@@ -215,7 +215,7 @@ class PendingReplicationBlocks {
     @Override
     public void run() {
       while (fsRunning) {
-        long period = Math.min(defaultRecheckInterval, timeout);
+        long period = Math.min(DEFAULT_RECHECK_INTERVAL, timeout);
         try {
           pendingReplicationCheck();
           Thread.sleep(period);

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/UnderReplicatedBlocks.java

@@ -78,7 +78,7 @@ class UnderReplicatedBlocks implements Iterable<Block> {
   /** The queue for corrupt blocks: {@value} */
   static final int QUEUE_WITH_CORRUPT_BLOCKS = 4;
   /** the queues themselves */
-  private List<LightWeightLinkedSet<Block>> priorityQueues
+  private final List<LightWeightLinkedSet<Block>> priorityQueues
       = new ArrayList<LightWeightLinkedSet<Block>>(LEVEL);
 
   /** Create an object. */
@@ -378,7 +378,7 @@ class UnderReplicatedBlocks implements Iterable<Block> {
   class BlockIterator implements Iterator<Block> {
     private int level;
     private boolean isIteratorForLevel = false;
-    private List<Iterator<Block>> iterators = new ArrayList<Iterator<Block>>();
+    private final List<Iterator<Block>> iterators = new ArrayList<Iterator<Block>>();
 
     /**
      * Construct an iterator over all queues.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/HdfsServerConstants.java

@@ -196,10 +196,10 @@ public final class HdfsServerConstants {
   }
 
   // Timeouts for communicating with DataNode for streaming writes/reads
-  public static int READ_TIMEOUT = 60 * 1000;
-  public static int READ_TIMEOUT_EXTENSION = 5 * 1000;
-  public static int WRITE_TIMEOUT = 8 * 60 * 1000;
-  public static int WRITE_TIMEOUT_EXTENSION = 5 * 1000; //for write pipeline
+  public static final int READ_TIMEOUT = 60 * 1000;
+  public static final int READ_TIMEOUT_EXTENSION = 5 * 1000;
+  public static final int WRITE_TIMEOUT = 8 * 60 * 1000;
+  public static final int WRITE_TIMEOUT_EXTENSION = 5 * 1000; //for write pipeline
 
   /**
    * Defines the NameNode role.
@@ -233,7 +233,7 @@ public final class HdfsServerConstants {
     /** Temporary replica: created for replication and relocation only. */
     TEMPORARY(4);
 
-    private int value;
+    private final int value;
 
     private ReplicaState(int v) {
       value = v;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/Storage.java

@@ -118,8 +118,8 @@ public abstract class Storage extends StorageInfo {
   protected List<StorageDirectory> storageDirs = new ArrayList<StorageDirectory>();
   
   private class DirIterator implements Iterator<StorageDirectory> {
-    StorageDirType dirType;
-    boolean includeShared;
+    final StorageDirType dirType;
+    final boolean includeShared;
     int prevIndex; // for remove()
     int nextIndex; // for next()
     

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/UpgradeStatusReport.java

@@ -27,9 +27,9 @@ import org.apache.hadoop.classification.InterfaceAudience;
  */
 @InterfaceAudience.Private
 public class UpgradeStatusReport {
-  protected int version;
-  protected short upgradeStatus;
-  protected boolean finalized;
+  protected final int version;
+  protected final short upgradeStatus;
+  protected final boolean finalized;
 
   public UpgradeStatusReport(int version, short status, boolean isFinalized) {
     this.version = version;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPOfferService.java

@@ -78,7 +78,7 @@ class BPOfferService {
    * The list of all actors for namenodes in this nameservice, regardless
    * of their active or standby states.
    */
-  private List<BPServiceActor> bpServices =
+  private final List<BPServiceActor> bpServices =
     new CopyOnWriteArrayList<BPServiceActor>();
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPServiceActor.java

@@ -74,7 +74,7 @@ class BPServiceActor implements Runnable {
   final InetSocketAddress nnAddr;
   HAServiceState state;
 
-  BPOfferService bpos;
+  final BPOfferService bpos;
   
   // lastBlockReport, lastDeletedReport and lastHeartbeat may be assigned/read
   // by testing threads (through BPServiceActor#triggerXXX), while also 
@@ -893,7 +893,7 @@ class BPServiceActor implements Runnable {
   }
 
   private static class PerStoragePendingIncrementalBR {
-    private Map<Long, ReceivedDeletedBlockInfo> pendingIncrementalBR =
+    private final Map<Long, ReceivedDeletedBlockInfo> pendingIncrementalBR =
         Maps.newHashMap();
 
     /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockMetadataHeader.java

@@ -54,7 +54,7 @@ public class BlockMetadataHeader {
    * Version is two bytes. Following it is the DataChecksum
    * that occupies 5 bytes. 
    */
-  private short version;
+  private final short version;
   private DataChecksum checksum = null;
     
   @VisibleForTesting

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolSliceScanner.java

@@ -361,7 +361,7 @@ class BlockPoolSliceScanner {
      * This simple text and easily extendable and easily parseable with a
      * regex.
      */
-    private static Pattern entryPattern = 
+    private static final Pattern entryPattern =
       Pattern.compile("\\G\\s*([^=\\p{Space}]+)=\"(.*?)\"\\s*");
     
     static String toString(long verificationTime, long genStamp, long blockId,

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockReceiver.java

@@ -86,7 +86,7 @@ class BlockReceiver implements Closeable {
   private int bytesPerChecksum;
   private int checksumSize;
   
-  private PacketReceiver packetReceiver =
+  private final PacketReceiver packetReceiver =
       new PacketReceiver(false);
   
   protected final String inAddr;
@@ -902,7 +902,7 @@ class BlockReceiver implements Closeable {
     NON_PIPELINE, LAST_IN_PIPELINE, HAS_DOWNSTREAM_IN_PIPELINE
   }
   
-  private static Status[] MIRROR_ERROR_STATUS = {Status.SUCCESS, Status.ERROR};
+  private static final Status[] MIRROR_ERROR_STATUS = {Status.SUCCESS, Status.ERROR};
   
   /**
    * Processes responses from downstream datanodes in the pipeline

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -185,7 +185,7 @@ public class DataNode extends Configured
   private String clusterId = null;
 
   public final static String EMPTY_DEL_HINT = "";
-  AtomicInteger xmitsInProgress = new AtomicInteger();
+  final AtomicInteger xmitsInProgress = new AtomicInteger();
   Daemon dataXceiverServer = null;
   Daemon localDataXceiverServer = null;
   ShortCircuitRegistry shortCircuitRegistry = null;
@@ -223,11 +223,11 @@ public class DataNode extends Configured
   private SecureResources secureResources = null;
   private List<StorageLocation> dataDirs;
   private Configuration conf;
-  private String confVersion;
+  private final String confVersion;
   private final long maxNumberOfBlocksToLog;
 
   private final List<String> usersWithLocalPathAccess;
-  private boolean connectToDnViaHostname;
+  private final boolean connectToDnViaHostname;
   ReadaheadPool readaheadPool;
   private final boolean getHdfsBlockLocationsEnabled;
   private ObjectName dataNodeInfoBeanName;
@@ -1836,7 +1836,7 @@ public class DataNode extends Configured
   // Small wrapper around the DiskChecker class that provides means to mock
   // DiskChecker static methods and unittest DataNode#getDataDirsFromURIs.
   static class DataNodeDiskChecker {
-    private FsPermission expectedPermission;
+    private final FsPermission expectedPermission;
 
     public DataNodeDiskChecker(FsPermission expectedPermission) {
       this.expectedPermission = expectedPermission;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataStorage.java

@@ -78,7 +78,7 @@ public class DataStorage extends Storage {
   private boolean initialized = false;
   
   // Maps block pool IDs to block pool storage
-  private Map<String, BlockPoolSliceStorage> bpStorageMap
+  private final Map<String, BlockPoolSliceStorage> bpStorageMap
       = Collections.synchronizedMap(new HashMap<String, BlockPoolSliceStorage>());
 
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiverServer.java

@@ -92,7 +92,7 @@ class DataXceiverServer implements Runnable {
    }
   }
 
-  BlockBalanceThrottler balanceThrottler;
+  final BlockBalanceThrottler balanceThrottler;
   
   /**
    * We need an estimate for block size to check if the disk partition has
@@ -102,7 +102,7 @@ class DataXceiverServer implements Runnable {
    * A better solution is to include in the header the estimated block size,
    * i.e. either the actual block size or the default block size.
    */
-  long estimateBlockSize;
+  final long estimateBlockSize;
   
   
   DataXceiverServer(PeerServer peerServer, Configuration conf,

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DirectoryScanner.java

@@ -64,8 +64,8 @@ public class DirectoryScanner implements Runnable {
   private volatile boolean shouldRun = false;
   private boolean retainDiffs = false;
 
-  ScanInfoPerBlockPool diffs = new ScanInfoPerBlockPool();
-  Map<String, Stats> stats = new HashMap<String, Stats>();
+  final ScanInfoPerBlockPool diffs = new ScanInfoPerBlockPool();
+  final Map<String, Stats> stats = new HashMap<String, Stats>();
   
   /**
    * Allow retaining diffs for unit test and analysis
@@ -77,7 +77,7 @@ public class DirectoryScanner implements Runnable {
 
   /** Stats tracked for reporting and testing, per blockpool */
   static class Stats {
-    String bpid;
+    final String bpid;
     long totalBlocks = 0;
     long missingMetaFile = 0;
     long missingBlockFile = 0;
@@ -570,7 +570,7 @@ public class DirectoryScanner implements Runnable {
 
   private static class ReportCompiler 
   implements Callable<ScanInfoPerBlockPool> {
-    private FsVolumeSpi volume;
+    private final FsVolumeSpi volume;
 
     public ReportCompiler(FsVolumeSpi volume) {
       this.volume = volume;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/AvailableSpaceVolumeChoosingPolicy.java

@@ -82,11 +82,11 @@ public class AvailableSpaceVolumeChoosingPolicy<V extends FsVolumeSpi>
     return null;
   }
   
-  private VolumeChoosingPolicy<V> roundRobinPolicyBalanced =
+  private final VolumeChoosingPolicy<V> roundRobinPolicyBalanced =
       new RoundRobinVolumeChoosingPolicy<V>();
-  private VolumeChoosingPolicy<V> roundRobinPolicyHighAvailable =
+  private final VolumeChoosingPolicy<V> roundRobinPolicyHighAvailable =
       new RoundRobinVolumeChoosingPolicy<V>();
-  private VolumeChoosingPolicy<V> roundRobinPolicyLowAvailable =
+  private final VolumeChoosingPolicy<V> roundRobinPolicyLowAvailable =
       new RoundRobinVolumeChoosingPolicy<V>();
 
   @Override

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/BlockPoolSlice.java

@@ -62,7 +62,7 @@ class BlockPoolSlice {
   private final LDir finalizedDir; // directory store Finalized replica
   private final File rbwDir; // directory store RBW replica
   private final File tmpDir; // directory store Temporary replica
-  private static String DU_CACHE_FILE = "dfsUsed";
+  private static final String DU_CACHE_FILE = "dfsUsed";
   private volatile boolean dfsUsedSaved = false;
   private static final int SHUTDOWN_HOOK_PRIORITY = 30;
   

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetCache.java

@@ -145,7 +145,7 @@ public class FsDatasetCache {
   private class UsedBytesCount {
     private final AtomicLong usedBytes = new AtomicLong(0);
     
-    private PageRounder rounder = new PageRounder();
+    private final PageRounder rounder = new PageRounder();
 
     /**
      * Try to reserve more bytes.
@@ -196,11 +196,11 @@ public class FsDatasetCache {
   /**
    * Number of cache commands that could not be completed successfully
    */
-  AtomicLong numBlocksFailedToCache = new AtomicLong(0);
+  final AtomicLong numBlocksFailedToCache = new AtomicLong(0);
   /**
    * Number of uncache commands that could not be completed successfully
    */
-  AtomicLong numBlocksFailedToUncache = new AtomicLong(0);
+  final AtomicLong numBlocksFailedToUncache = new AtomicLong(0);
 
   public FsDatasetCache(FsDatasetImpl dataset) {
     this.dataset = dataset;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/ReplicaMap.java

@@ -33,7 +33,7 @@ class ReplicaMap {
   private final Object mutex;
   
   // Map of block pool Id to another map of block Id to ReplicaInfo.
-  private Map<String, Map<Long, ReplicaInfo>> map = 
+  private final Map<String, Map<Long, ReplicaInfo>> map =
     new HashMap<String, Map<Long, ReplicaInfo>>();
   
   ReplicaMap(Object mutex) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/RollingLogsImpl.java

@@ -46,7 +46,7 @@ class RollingLogsImpl implements RollingLogs {
   private final File prev;
   private PrintWriter out; //require synchronized access
 
-  private Appender appender = new Appender() {
+  private final Appender appender = new Appender() {
     @Override
     public Appendable append(CharSequence csq) {
       synchronized(RollingLogsImpl.this) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/metrics/DataNodeMetrics.java

@@ -78,18 +78,18 @@ public class DataNodeMetrics {
   @Metric MutableRate blockReports;
   @Metric MutableRate cacheReports;
   @Metric MutableRate packetAckRoundTripTimeNanos;
-  MutableQuantiles[] packetAckRoundTripTimeNanosQuantiles;
+  final MutableQuantiles[] packetAckRoundTripTimeNanosQuantiles;
   
   @Metric MutableRate flushNanos;
-  MutableQuantiles[] flushNanosQuantiles;
+  final MutableQuantiles[] flushNanosQuantiles;
   
   @Metric MutableRate fsyncNanos;
-  MutableQuantiles[] fsyncNanosQuantiles;
+  final MutableQuantiles[] fsyncNanosQuantiles;
   
   @Metric MutableRate sendDataPacketBlockedOnNetworkNanos;
-  MutableQuantiles[] sendDataPacketBlockedOnNetworkNanosQuantiles;
+  final MutableQuantiles[] sendDataPacketBlockedOnNetworkNanosQuantiles;
   @Metric MutableRate sendDataPacketTransferNanos;
-  MutableQuantiles[] sendDataPacketTransferNanosQuantiles;
+  final MutableQuantiles[] sendDataPacketTransferNanosQuantiles;
   
 
   final MetricsRegistry registry = new MetricsRegistry("datanode");

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

@@ -41,7 +41,7 @@ import com.google.common.collect.Lists;
 @InterfaceAudience.Private
 public class BackupImage extends FSImage {
   /** Backup input stream for loading edits into memory */
-  private EditLogBackupInputStream backupInputStream =
+  private final EditLogBackupInputStream backupInputStream =
     new EditLogBackupInputStream("Data from remote NameNode");
   
   /**

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

@@ -85,7 +85,7 @@ public final class CachePool {
 
   public final static class DirectiveList
       extends IntrusiveCollection<CacheDirective> {
-    private CachePool cachePool;
+    private final CachePool cachePool;
 
     private DirectiveList(CachePool cachePool) {
       this.cachePool = cachePool;

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

@@ -59,7 +59,7 @@ class Checkpointer extends Daemon {
   public static final Log LOG = 
     LogFactory.getLog(Checkpointer.class.getName());
 
-  private BackupNode backupNode;
+  private final BackupNode backupNode;
   volatile boolean shouldRun;
 
   private String infoBindAddress;

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

@@ -33,8 +33,8 @@ import com.google.common.base.Preconditions;
  *  int, int, byte[])
  */
 class EditLogBackupInputStream extends EditLogInputStream {
-  String address; // sender address 
-  private ByteBufferInputStream inner;
+  final String address; // sender address
+  private final ByteBufferInputStream inner;
   private DataInputStream in;
   private FSEditLogOp.Reader reader = null;
   private FSEditLogLoader.PositionTrackingInputStream tracker = null;

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

@@ -43,8 +43,8 @@ import org.apache.hadoop.security.UserGroupInformation;
  *  int, int, byte[])
  */
 class EditLogBackupOutputStream extends EditLogOutputStream {
-  private static Log LOG = LogFactory.getLog(EditLogFileOutputStream.class);
-  static int DEFAULT_BUFFER_SIZE = 256;
+  private static final Log LOG = LogFactory.getLog(EditLogFileOutputStream.class);
+  static final int DEFAULT_BUFFER_SIZE = 256;
 
   private final JournalProtocol backupNode;  // RPC proxy to backup node
   private final NamenodeRegistration bnRegistration;  // backup node registration

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

@@ -42,14 +42,14 @@ import com.google.common.annotations.VisibleForTesting;
  */
 @InterfaceAudience.Private
 public class EditLogFileOutputStream extends EditLogOutputStream {
-  private static Log LOG = LogFactory.getLog(EditLogFileOutputStream.class);
+  private static final Log LOG = LogFactory.getLog(EditLogFileOutputStream.class);
   public static final int MIN_PREALLOCATION_LENGTH = 1024 * 1024;
 
   private File file;
   private FileOutputStream fp; // file stream for storing edit logs
   private FileChannel fc; // channel of the file stream for sync
   private EditsDoubleBuffer doubleBuf;
-  static ByteBuffer fill = ByteBuffer.allocateDirect(MIN_PREALLOCATION_LENGTH);
+  static final ByteBuffer fill = ByteBuffer.allocateDirect(MIN_PREALLOCATION_LENGTH);
   private boolean shouldSyncWritesAndSkipFsync = false;
 
   private static boolean shouldSkipFsyncForTests = false;

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

@@ -132,7 +132,7 @@ public class EditsDoubleBuffer {
   private static class TxnBuffer extends DataOutputBuffer {
     long firstTxId;
     int numTxns;
-    private Writer writer;
+    private final Writer writer;
     
     public TxnBuffer(int initBufferSize) {
       super(initBufferSize);

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

@@ -125,8 +125,8 @@ public class FSDirectory implements Closeable {
   private long yieldCount = 0; // keep track of lock yield count.
 
   // lock to protect the directory and BlockMap
-  private ReentrantReadWriteLock dirLock;
-  private Condition cond;
+  private final ReentrantReadWriteLock dirLock;
+  private final Condition cond;
 
   // utility methods to acquire and release read lock and write lock
   void readLock() {

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

@@ -172,7 +172,7 @@ public class FSEditLog implements LogsPurgeable {
   
   private final List<URI> editsDirs;
 
-  private ThreadLocal<OpInstanceCache> cache =
+  private final ThreadLocal<OpInstanceCache> cache =
       new ThreadLocal<OpInstanceCache>() {
     @Override
     protected OpInstanceCache initialValue() {

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

@@ -136,7 +136,7 @@ public abstract class FSEditLogOp {
   int rpcCallId = RpcConstants.INVALID_CALL_ID;
 
   final public static class OpInstanceCache {
-    private EnumMap<FSEditLogOpCodes, FSEditLogOp> inst = 
+    private final EnumMap<FSEditLogOpCodes, FSEditLogOp> inst =
         new EnumMap<FSEditLogOpCodes, FSEditLogOp>(FSEditLogOpCodes.class);
     
     public OpInstanceCache() {

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

@@ -94,7 +94,7 @@ public enum FSEditLogOpCodes {
     return opCode;
   }
 
-  private static FSEditLogOpCodes[] VALUES;
+  private static final FSEditLogOpCodes[] VALUES;
   
   static {
     byte max = 0;

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

@@ -940,7 +940,7 @@ public class FSImage implements Closeable {
    */
   private class FSImageSaver implements Runnable {
     private final SaveNamespaceContext context;
-    private StorageDirectory sd;
+    private final StorageDirectory sd;
     private final NameNodeFile nnf;
 
     public FSImageSaver(SaveNamespaceContext context, StorageDirectory sd,

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

@@ -903,7 +903,7 @@ public class FSImageFormat {
   }
 
   @VisibleForTesting
-  public static TreeMap<String, String> renameReservedMap =
+  public static final TreeMap<String, String> renameReservedMap =
       new TreeMap<String, String>();
 
   /**

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

@@ -68,10 +68,10 @@ class FSImagePreTransactionalStorageInspector extends FSImageStorageInspector {
   private StorageDirectory latestEditsSD = null;
 
   /** Set to determine if all of storageDirectories share the same checkpoint */
-  Set<Long> checkpointTimes = new HashSet<Long>();
+  final Set<Long> checkpointTimes = new HashSet<Long>();
 
-  private List<String> imageDirs = new ArrayList<String>();
-  private List<String> editsDirs = new ArrayList<String>();
+  private final List<String> imageDirs = new ArrayList<String>();
+  private final List<String> editsDirs = new ArrayList<String>();
   
   @Override
   void inspectDirectory(StorageDirectory sd) throws IOException {

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

@@ -45,7 +45,7 @@ class FSImageTransactionalStorageInspector extends FSImageStorageInspector {
   private boolean needToSave = false;
   private boolean isUpgradeFinalized = true;
   
-  List<FSImageFile> foundImages = new ArrayList<FSImageFile>();
+  final List<FSImageFile> foundImages = new ArrayList<FSImageFile>();
   private long maxSeenTxId = 0;
   
   private final List<Pattern> namePatterns = Lists.newArrayList();

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

@@ -488,7 +488,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   private final long accessTimePrecision;
 
   /** Lock to protect FSNamesystem. */
-  private FSNamesystemLock fsLock;
+  private final FSNamesystemLock fsLock;
 
   /**
    * Used when this NN is in standby state to read from the shared edit log.
@@ -4653,15 +4653,15 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   public class SafeModeInfo {
     // configuration fields
     /** Safe mode threshold condition %.*/
-    private double threshold;
+    private final double threshold;
     /** Safe mode minimum number of datanodes alive */
-    private int datanodeThreshold;
+    private final int datanodeThreshold;
     /** Safe mode extension after the threshold. */
     private int extension;
     /** Min replication required by safe mode. */
-    private int safeReplication;
+    private final int safeReplication;
     /** threshold for populating needed replication queues */
-    private double replQueueThreshold;
+    private final double replQueueThreshold;
     // internal fields
     /** Time when threshold was reached.
      * <br> -1 safe mode is off
@@ -6097,8 +6097,8 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   }
 
   static class CorruptFileBlockInfo {
-    String path;
-    Block block;
+    final String path;
+    final Block block;
     
     public CorruptFileBlockInfo(String p, Block b) {
       path = p;

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

@@ -50,7 +50,7 @@ class FSNamesystemLock implements ReadWriteLock {
    * See HDFS-5064 for more context.
    */
   @VisibleForTesting
-  protected ReentrantLock longReadLock = new ReentrantLock(true);
+  protected final ReentrantLock longReadLock = new ReentrantLock(true);
   
   FSNamesystemLock(boolean fair) {
     this.coarseLock = new ReentrantReadWriteLock(fair);

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

@@ -168,7 +168,7 @@ public class HostFileManager {
      * The different indexing strategies reflect the fact that we may or may
      * not have a port or IP address for each entry.
      */
-    TreeMap<String, Entry> index = new TreeMap<String, Entry>();
+    final TreeMap<String, Entry> index = new TreeMap<String, Entry>();
 
     public boolean isEmpty() {
       return index.isEmpty();

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

@@ -750,7 +750,7 @@ public abstract class INode implements INodeAttributes, Diff.Element<byte[]> {
     /**
      * The list of blocks that need to be removed from blocksMap
      */
-    private List<Block> toDeleteList;
+    private final List<Block> toDeleteList;
     
     public BlocksMapUpdateInfo() {
       toDeleteList = new ChunkedArrayList<Block>();

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

@@ -81,7 +81,7 @@ public class ImageServlet extends HttpServlet {
   private static final String LATEST_FSIMAGE_VALUE = "latest";
   private static final String IMAGE_FILE_TYPE = "imageFile";
 
-  private static Set<Long> currentlyDownloadingCheckpoints =
+  private static final Set<Long> currentlyDownloadingCheckpoints =
     Collections.<Long>synchronizedSet(new HashSet<Long>());
   
   @Override

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

@@ -177,7 +177,7 @@ public class JournalSet implements JournalManager {
   // COW implementation is necessary since some users (eg the web ui) call
   // getAllJournalStreams() and then iterate. Since this is rarely
   // mutated, there is no performance concern.
-  private List<JournalAndStream> journals =
+  private final List<JournalAndStream> journals =
       new CopyOnWriteArrayList<JournalSet.JournalAndStream>();
   final int minimumRedundantJournals;
   

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

@@ -77,15 +77,15 @@ public class LeaseManager {
   // Used for handling lock-leases
   // Mapping: leaseHolder -> Lease
   //
-  private SortedMap<String, Lease> leases = new TreeMap<String, Lease>();
+  private final SortedMap<String, Lease> leases = new TreeMap<String, Lease>();
   // Set of: Lease
-  private SortedSet<Lease> sortedLeases = new TreeSet<Lease>();
+  private final SortedSet<Lease> sortedLeases = new TreeSet<Lease>();
 
   // 
   // Map path names to leases. It is protected by the sortedLeases lock.
   // The map stores pathnames in lexicographical order.
   //
-  private SortedMap<String, Lease> sortedLeasesByPath = new TreeMap<String, Lease>();
+  private final SortedMap<String, Lease> sortedLeasesByPath = new TreeMap<String, Lease>();
 
   private Daemon lmthread;
   private volatile boolean shouldRunMonitor;

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

@@ -117,7 +117,7 @@ public class NNStorage extends Storage implements Closeable,
    * flag that controls if we try to restore failed storages
    */
   private boolean restoreFailedStorage = false;
-  private Object restorationLock = new Object();
+  private final Object restorationLock = new Object();
   private boolean disablePreUpgradableLayoutCheck = false;
 
 

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

@@ -249,11 +249,11 @@ public class NameNode implements NameNodeStatusMXBean {
   
   protected FSNamesystem namesystem; 
   protected final Configuration conf;
-  protected NamenodeRole role;
+  protected final NamenodeRole role;
   private volatile HAState state;
   private final boolean haEnabled;
   private final HAContext haContext;
-  protected boolean allowStaleStandbyReads;
+  protected final boolean allowStaleStandbyReads;
 
   
   /** httpServer */

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

@@ -52,7 +52,7 @@ public class NameNodeHttpServer {
   
   private InetSocketAddress httpAddress;
   private InetSocketAddress httpsAddress;
-  private InetSocketAddress bindAddress;
+  private final InetSocketAddress bindAddress;
   
   public static final String NAMENODE_ADDRESS_ATTRIBUTE_KEY = "name.node.address";
   public static final String FSIMAGE_ATTRIBUTE_KEY = "name.system.image";

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

@@ -50,7 +50,7 @@ public class NameNodeResourceChecker {
   private static final Log LOG = LogFactory.getLog(NameNodeResourceChecker.class.getName());
 
   // Space (in bytes) reserved per volume.
-  private long duReserved;
+  private final long duReserved;
 
   private final Configuration conf;
   private Map<String, CheckedVolume> volumes;

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

@@ -144,13 +144,13 @@ public class NamenodeFsck {
   // We return back N files that are corrupt; the list of files returned is
   // ordered by block id; to allow continuation support, pass in the last block
   // # from previous call
-  private String[] currentCookie = new String[] { null };
+  private final String[] currentCookie = new String[] { null };
 
   private final Configuration conf;
   private final PrintWriter out;
   private List<String> snapshottableDirs = null;
 
-  private BlockPlacementPolicy bpPolicy;
+  private final BlockPlacementPolicy bpPolicy;
 
   /**
    * Filesystem checker.
@@ -716,7 +716,7 @@ public class NamenodeFsck {
    */
   @VisibleForTesting
   static class Result {
-    List<String> missingIds = new ArrayList<String>();
+    final List<String> missingIds = new ArrayList<String>();
     long missingSize = 0L;
     long corruptFiles = 0L;
     long corruptBlocks = 0L;

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

@@ -41,7 +41,7 @@ public class SaveNamespaceContext {
     Collections.synchronizedList(new ArrayList<StorageDirectory>());
   
   private final Canceler canceller;
-  private CountDownLatch completionLatch = new CountDownLatch(1);
+  private final CountDownLatch completionLatch = new CountDownLatch(1);
 
   SaveNamespaceContext(
       FSNamesystem sourceNamesystem,

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

@@ -794,8 +794,8 @@ public class SecondaryNameNode implements Runnable {
     private int mergeErrorCount;
     private static class CheckpointLogPurger implements LogsPurgeable {
       
-      private NNStorage storage;
-      private StoragePurger purger
+      private final NNStorage storage;
+      private final StoragePurger purger
           = new NNStorageRetentionManager.DeletionStoragePurger();
       
       public CheckpointLogPurger(NNStorage storage) {

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

@@ -27,8 +27,8 @@ class SerialNumberManager {
   /** This is the only instance of {@link SerialNumberManager}.*/
   static final SerialNumberManager INSTANCE = new SerialNumberManager();
 
-  private SerialNumberMap<String> usermap = new SerialNumberMap<String>();
-  private SerialNumberMap<String> groupmap = new SerialNumberMap<String>();
+  private final SerialNumberMap<String> usermap = new SerialNumberMap<String>();
+  private final SerialNumberMap<String> groupmap = new SerialNumberMap<String>();
 
   private SerialNumberManager() {}
 
@@ -43,9 +43,9 @@ class SerialNumberManager {
   }
 
   private static class SerialNumberMap<T> {
-    private AtomicInteger max = new AtomicInteger(1);
-    private ConcurrentMap<T, Integer> t2i = new ConcurrentHashMap<T, Integer>();
-    private ConcurrentMap<Integer, T> i2t = new ConcurrentHashMap<Integer, T>();
+    private final AtomicInteger max = new AtomicInteger(1);
+    private final ConcurrentMap<T, Integer> t2i = new ConcurrentHashMap<T, Integer>();
+    private final ConcurrentMap<Integer, T> i2t = new ConcurrentHashMap<Integer, T>();
 
     int get(T t) {
       if (t == null) {

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

@@ -79,8 +79,8 @@ public class TransferFsImage {
 
   @VisibleForTesting
   static int timeout = 0;
-  private static URLConnectionFactory connectionFactory;
-  private static boolean isSpnegoEnabled;
+  private static final URLConnectionFactory connectionFactory;
+  private static final boolean isSpnegoEnabled;
 
   static {
     Configuration conf = new Configuration();

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

@@ -141,7 +141,7 @@ public class ConfiguredFailoverProxyProvider<T> implements
    * an NN. Note that {@link AddressRpcProxyPair#namenode} may be null.
    */
   private static class AddressRpcProxyPair<T> {
-    public InetSocketAddress address;
+    public final InetSocketAddress address;
     public T namenode;
     
     public AddressRpcProxyPair(InetSocketAddress address) {