HDFS-16599. Fix typo in hadoop-hdfs-rbf module (#4368). Contributed by fanshilun.

Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/rbfbalance/RouterFedBalance.java

@@ -63,7 +63,7 @@
  * dst sub-namespace with distcp.
  *
  * 1. Move data from the source path to the destination path with distcp.
- * 2. Update the the mount entry.
+ * 2. Update the mount entry.
  * 3. Delete the source path to trash.
  */
 public class RouterFedBalance extends Configured implements Tool {
@@ -77,7 +77,7 @@ public class RouterFedBalance extends Configured implements Tool {
   private static final String TRASH_PROCEDURE = "trash-procedure";
 
   /**
-   * This class helps building the balance job.
+   * This class helps to build the balance job.
    */
   private class Builder {
     /* Force close all open files while there is no diff. */

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/FederationMBean.java

@@ -50,7 +50,7 @@ public interface FederationMBean {
 
   /**
    * Get the latest state of all routers.
-   * @return JSON with all of the known routers or null if failure.
+   * @return JSON with all the known routers or null if failure.
    */
   String getRouters();
 

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/FederationRPCPerformanceMonitor.java

@@ -52,7 +52,7 @@ public class FederationRPCPerformanceMonitor implements RouterRpcMonitor {
 
   /** Time for an operation to be received in the Router. */
   private static final ThreadLocal<Long> START_TIME = new ThreadLocal<>();
-  /** Time for an operation to be send to the Namenode. */
+  /** Time for an operation to be sent to the Namenode. */
   private static final ThreadLocal<Long> PROXY_TIME = new ThreadLocal<>();
 
   /** Configuration for the performance monitor. */

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/RBFMetrics.java

@@ -290,7 +290,7 @@ public String getMountTable() {
 
       // Dump mount table entries information into JSON
       for (MountTable entry : orderedMounts) {
-        // Sumarize destinations
+        // Summarize destinations
         Set<String> nameservices = new LinkedHashSet<>();
         Set<String> paths = new LinkedHashSet<>();
         for (RemoteLocation location : entry.getDestinations()) {

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/ConnectionContext.java

@@ -124,7 +124,7 @@ public synchronized void release() {
    */
   public synchronized void close(boolean force) {
     if (!force && this.numThreads > 0) {
-      // this is an erroneous case but we have to close the connection
+      // this is an erroneous case, but we have to close the connection
       // anyway since there will be connection leak if we don't do so
       // the connection has been moved out of the pool
       LOG.error("Active connection with {} handlers will be closed",
@@ -132,7 +132,7 @@ public synchronized void close(boolean force) {
     }
     this.closed = true;
     Object proxy = this.client.getProxy();
-    // Nobody should be using this anymore so it should close right away
+    // Nobody should be using this anymore, so it should close right away
     RPC.stopProxy(proxy);
   }
 

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/ConnectionManager.java

@@ -135,12 +135,12 @@ public void start() {
     this.creator.start();
 
     // Schedule a task to remove stale connection pools and sockets
-    long recyleTimeMs = Math.min(
+    long recycleTimeMs = Math.min(
         poolCleanupPeriodMs, connectionCleanupPeriodMs);
     LOG.info("Cleaning every {} seconds",
-        TimeUnit.MILLISECONDS.toSeconds(recyleTimeMs));
+        TimeUnit.MILLISECONDS.toSeconds(recycleTimeMs));
     this.cleaner.scheduleAtFixedRate(
-        new CleanupTask(), 0, recyleTimeMs, TimeUnit.MILLISECONDS);
+        new CleanupTask(), 0, recycleTimeMs, TimeUnit.MILLISECONDS);
 
     // Mark the manager as running
     this.running = true;
@@ -364,9 +364,9 @@ void cleanup(ConnectionPool pool) {
       long timeSinceLastActive = Time.now() - pool.getLastActiveTime();
       int total = pool.getNumConnections();
       // Active is a transient status in many cases for a connection since
-      // the handler thread uses the connection very quickly. Thus the number
+      // the handler thread uses the connection very quickly. Thus, the number
       // of connections with handlers using at the call time is constantly low.
-      // Recently active is more lasting status and it shows how many
+      // Recently active is more lasting status, and it shows how many
       // connections have been used with a recent time period. (i.e. 30 seconds)
       int active = pool.getNumActiveConnectionsRecently();
       float poolMinActiveRatio = pool.getMinActiveRatio();
@@ -376,9 +376,9 @@ void cleanup(ConnectionPool pool) {
         // The number should at least be 1
         int targetConnectionsCount = Math.max(1,
             (int)(poolMinActiveRatio * total) - active);
-        List<ConnectionContext> conns =
+        List<ConnectionContext> connections =
             pool.removeConnections(targetConnectionsCount);
-        for (ConnectionContext conn : conns) {
+        for (ConnectionContext conn : connections) {
           conn.close();
         }
         LOG.debug("Removed connection {} used {} seconds ago. " +

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/FederationUtil.java

@@ -231,7 +231,7 @@ public static ActiveNamenodeResolver newActiveNamenodeResolver(
   }
 
   /**
-   * Add the the number of children for an existing HdfsFileStatus object.
+   * Add the number of children for an existing HdfsFileStatus object.
    * @param dirStatus HdfsfileStatus object.
    * @param children number of children to be added.
    * @return HdfsFileStatus with the number of children specified.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/MountTableRefresherThread.java

@@ -50,14 +50,14 @@ public MountTableRefresherThread(MountTableManager manager,
 
   /**
    * Refresh mount table cache of local and remote routers. Local and remote
-   * routers will be refreshed differently. Lets understand what are the
+   * routers will be refreshed differently. Let's understand what are the
    * local and remote routers and refresh will be done differently on these
    * routers. Suppose there are three routers R1, R2 and R3. User want to add
    * new mount table entry. He will connect to only one router, not all the
    * routers. Suppose He connects to R1 and calls add mount table entry through
    * API or CLI. Now in this context R1 is local router, R2 and R3 are remote
    * routers. Because add mount table entry is invoked on R1, R1 will update the
-   * cache locally it need not to make RPC call. But R1 will make RPC calls to
+   * cache locally it need not make RPC call. But R1 will make RPC calls to
    * update cache on R2 and R3.
    */
   @Override

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RBFConfigKeys.java

@@ -255,7 +255,7 @@ public class RBFConfigKeys extends CommonConfigurationKeysPublic {
       TimeUnit.MINUTES.toMillis(1);
   /**
    * Remote router mount table cache is updated through RouterClient(RPC call).
-   * To improve performance, RouterClient connections are cached but it should
+   * To improve performance, RouterClient connections are cached, but it should
    * not be kept in cache forever. This property defines the max time a
    * connection can be cached.
    */

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RemoteMethod.java

@@ -36,7 +36,7 @@ public class RemoteMethod {
   private static final Logger LOG = LoggerFactory.getLogger(RemoteMethod.class);
 
 
-  /** List of parameters: static and dynamic values, matchings types. */
+  /** List of parameters: static and dynamic values, matching types. */
   private final Object[] params;
   /** List of method parameters types, matches parameters. */
   private final Class<?>[] types;

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterAdminServer.java

@@ -104,7 +104,7 @@
 import org.apache.hadoop.thirdparty.protobuf.BlockingService;
 
 /**
- * This class is responsible for handling all of the Admin calls to the HDFS
+ * This class is responsible for handling all the Admin calls to the HDFS
  * router. It is created, started, and stopped by {@link Router}.
  */
 public class RouterAdminServer extends AbstractService

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterClientProtocol.java

@@ -305,7 +305,7 @@ public HdfsFileStatus create(String src, FsPermission masked,
    * Check if an exception is caused by an unavailable subcluster or not. It
    * also checks the causes.
    * @param ioe IOException to check.
-   * @return If caused by an unavailable subcluster. False if the should not be
+   * @return If caused by an unavailable subcluster. False if they should not be
    *         retried (e.g., NSQuotaExceededException).
    */
   protected static boolean isUnavailableSubclusterException(

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterQuotaUpdateService.java

@@ -200,7 +200,7 @@ private List<MountTable> getMountTableEntries() throws IOException {
    * During this time, the quota usage cache will also be updated by
    * quota manager:
    * 1. Stale paths (entries) will be removed.
-   * 2. Existing entries will be override and updated.
+   * 2. Existing entries will be overridden and updated.
    * @return List of mount tables which quota was set.
    * @throws IOException
    */

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcClient.java

@@ -139,7 +139,7 @@ public class RouterRpcClient {
   /**
    * Create a router RPC client to manage remote procedure calls to NNs.
    *
-   * @param conf Hdfs Configuation.
+   * @param conf Hdfs Configuration.
    * @param router A router using this RPC client.
    * @param resolver A NN resolver to determine the currently active NN in HA.
    * @param monitor Optional performance monitor.
@@ -444,7 +444,7 @@ private RetryDecision shouldRetry(final IOException ioe, final int retryCount,
    * @param ugi User group information.
    * @param namenodes A prioritized list of namenodes within the same
    *                  nameservice.
-   * @param method Remote ClientProtcol method to invoke.
+   * @param method Remote ClientProtocol method to invoke.
    * @param params Variable list of parameters matching the method.
    * @return The result of invoking the method.
    * @throws ConnectException If it cannot connect to any Namenode.
@@ -1027,7 +1027,7 @@ public <R extends RemoteLocationContext, T> RemoteResult invokeSequential(
       } catch (Exception e) {
         // Unusual error, ClientProtocol calls always use IOException (or
         // RemoteException). Re-wrap in IOException for compatibility with
-        // ClientProtcol.
+        // ClientProtocol.
         LOG.error("Unexpected exception {} proxying {} to {}",
             e.getClass(), m.getName(), ns, e);
         IOException ioe = new IOException(
@@ -1449,7 +1449,7 @@ public <T extends RemoteLocationContext, R> Map<T, R> invokeConcurrent(
           results.add(new RemoteResult<>(location, ioe));
         } catch (ExecutionException ex) {
           Throwable cause = ex.getCause();
-          LOG.debug("Canot execute {} in {}: {}",
+          LOG.debug("Cannot execute {} in {}: {}",
               m.getName(), location, cause.getMessage());
 
           // Convert into IOException if needed

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcMonitor.java

@@ -54,7 +54,7 @@ void init(
 
   /**
    * Start proxying an operation to the Namenode.
-   * @return Id of the thread doing the proxying.
+   * @return id of the thread doing the proxying.
    */
   long proxyOp();
 

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterWebHdfsMethods.java

@@ -410,7 +410,7 @@ protected Response get(
    * @param path Path to check.
    * @param op Operation to perform.
    * @param openOffset Offset for opening a file.
-   * @param excludeDatanodes Blocks to excluded.
+   * @param excludeDatanodes Blocks to exclude.
    * @param parameters Other parameters.
    * @return Redirection URI.
    * @throws URISyntaxException If it cannot parse the URI.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/store/CachedRecordStore.java

@@ -85,7 +85,7 @@ protected CachedRecordStore(Class<R> clazz, StateStoreDriver driver) {
    *
    * @param clazz Class of the record to store.
    * @param driver State Store driver.
-   * @param over If the entries should be override if they expire
+   * @param over If the entries should be overridden if they expire
    */
   protected CachedRecordStore(
       Class<R> clazz, StateStoreDriver driver, boolean over) {
@@ -153,7 +153,7 @@ public boolean loadCache(boolean force) throws IOException {
   }
 
   /**
-   * Check if it's time to update the cache. Update it it was never updated.
+   * Check if it's time to update the cache. Update it was never updated.
    *
    * @return If it's time to update this cache.
    */
@@ -206,7 +206,7 @@ public void overrideExpiredRecords(QueryResult<R> query) throws IOException {
    * Updates the state store with any record overrides we detected, such as an
    * expired state.
    *
-   * @param record Record record to be updated.
+   * @param record record to be updated.
    * @throws IOException If the values cannot be updated.
    */
   public void overrideExpiredRecord(R record) throws IOException {

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/store/StateStoreService.java

@@ -331,7 +331,7 @@ public StateStoreDriver getDriver() {
   }
 
   /**
-   * Fetch a unique identifier for this state store instance. Typically it is
+   * Fetch a unique identifier for this state store instance. Typically, it is
    * the address of the router.
    *
    * @return Unique identifier for this store.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/store/driver/StateStoreDriver.java

@@ -97,7 +97,7 @@ protected Configuration getConf() {
   }
 
   /**
-   * Gets a unique identifier for the running task/process. Typically the
+   * Gets a unique identifier for the running task/process. Typically, the
    * router address.
    *
    * @return Unique identifier for the running task.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/store/protocol/GetRouterRegistrationsRequest.java

@@ -22,7 +22,7 @@
 import org.apache.hadoop.hdfs.server.federation.store.driver.StateStoreSerializer;
 
 /**
- * API request for retrieving a all non-expired router registrations present in
+ * API request for retrieving an all non-expired router registrations present in
  * the state store.
  */
 public abstract class GetRouterRegistrationsRequest {

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/store/protocol/impl/pb/FederationProtocolPBTranslator.java

@@ -92,7 +92,7 @@ public B getBuilder() {
 
   /**
    * Get the serialized proto object. If the translator was created from a byte
-   * stream, returns the intitial byte stream. Otherwise creates a new byte
+   * stream, returns the initial byte stream. Otherwise, creates a new byte
    * stream from the cached builder.
    *
    * @return Protobuf message object

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/tools/federation/RouterAdmin.java

@@ -193,7 +193,7 @@ private String getUsage(String cmd) {
 
   /**
    * Usage: validates the maximum number of arguments for a command.
-   * @param arg List of of command line parameters.
+   * @param arg List of command line parameters.
    */
   private void validateMax(String[] arg) {
     if (arg[0].equals("-ls")) {
@@ -407,7 +407,7 @@ public int run(String[] argv) throws Exception {
       System.err.println(cmd.substring(1) + ": " + arge.getLocalizedMessage());
       printUsage(cmd);
     } catch (RemoteException e) {
-      // This is a error returned by the server.
+      // This is an error returned by the server.
       // Print out the first line of the error message, ignore the stack trace.
       exitCode = -1;
       debugException = e;
@@ -807,7 +807,7 @@ public void listMounts(String[] argv, int i) throws IOException {
     } else if (argv[i].equals("-d")) { // Check if -d parameter is specified.
       detail = true;
       if (argv.length == 2) {
-        path = "/"; // If no path is provide with -ls -d.
+        path = "/"; // If no path is provided with -ls -d.
       } else {
         path = argv[++i];
       }

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/MiniRouterDFSCluster.java

@@ -789,7 +789,7 @@ public void startCluster(Configuration overrideConf) {
       Configuration nnConf = generateNamenodeConfiguration(ns0);
       if (overrideConf != null) {
         nnConf.addResource(overrideConf);
-        // Router also uses this configurations as initial values.
+        // Router also uses these configurations as initial values.
         routerConf = new Configuration(overrideConf);
       }
 

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/MockResolver.java

@@ -137,7 +137,7 @@ public void updateActiveNamenode(
           break;
         }
       }
-      // This operation modifies the list so we need to be careful
+      // This operation modifies the list, so we need to be careful
       synchronized(namenodes) {
         Collections.sort(namenodes, new NamenodePriorityComparator());
       }

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/resolver/TestNamenodeResolver.java

@@ -297,7 +297,7 @@ public void testCacheUpdateOnNamenodeStateUpdate() throws IOException {
     String rpcAddr = namenode.getRpcAddress();
     InetSocketAddress inetAddr = getInetSocketAddress(rpcAddr);
 
-    // If the namenode state changes and it serves request,
+    // If the namenode state changes, and it serves request,
     // RouterRpcClient calls updateActiveNamenode to update the state to active,
     // Check whether correct updated state is returned post update.
     namenodeResolver.updateActiveNamenode(NAMESERVICES[0], inetAddr);

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouter.java

@@ -45,7 +45,7 @@
 import org.junit.Test;
 
 /**
- * The the safe mode for the {@link Router} controlled by
+ * The safe mode for the {@link Router} controlled by
  * {@link SafeModeTimer}.
  */
 public class TestRouter {

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterAdminCLI.java

@@ -742,7 +742,7 @@ public void testMountTablePermissions() throws Exception {
    * @param mount
    *          target mount table
    * @param canRead
-   *          whether can list mount tables under specified mount
+   *          whether you can list mount tables under specified mount
    * @param addCommandCode
    *          expected return code of add command executed for specified mount
    * @param rmCommandCode
@@ -1467,7 +1467,7 @@ public void testUpdateErrorCase() throws Exception {
         err.toString().contains("update: /noMount doesn't exist."));
     err.reset();
 
-    // Check update if non true/false value is passed for readonly.
+    // Check update if no true/false value is passed for readonly.
     argv = new String[] {"-update", src, "-readonly", "check"};
     assertEquals(-1, ToolRunner.run(admin, argv));
     assertTrue(err.toString(), err.toString().contains("update: "

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterFaultTolerant.java

@@ -582,7 +582,7 @@ public String toString() {
   }
 
   /**
-   * Asserts that the results are the expected amount and it has both success
+   * Asserts that the results are the expected amount, and it has both success
    * and failure.
    * @param msg Message to show when the assertion fails.
    * @param expected Expected number of results.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterMountTableCacheRefresh.java

@@ -308,9 +308,9 @@ public void run() {
         TimeUnit.SECONDS);
     mountTableRefresherService.init(config);
     // One router is not responding for 1 minute, still refresh should
-    // finished in 5 second as cache update timeout is set 5 second.
+    // finish in 5 second as cache update timeout is set 5 second.
     mountTableRefresherService.refresh();
-    // Test case timeout is assert for this test case.
+    // Test case timeout is asserted for this test case.
   }
 
   /**
@@ -349,7 +349,7 @@ protected RouterClient createRouterClient(
     mountTableRefresherService.refresh();
     assertNotEquals("No RouterClient is created.", 0, createCounter.get());
     /*
-     * Wait for clients to expire. Lets wait triple the cache eviction period.
+     * Wait for clients to expire. Let's wait triple the cache eviction period.
      * After cache eviction period all created client must be removed and
      * closed.
      */

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterQuotaManager.java

@@ -75,11 +75,11 @@ public void testGetChildrenPaths() {
   public void testGetQuotaUsage() {
     RouterQuotaUsage quotaGet;
 
-    // test case1: get quota with an non-exist path
+    // test case1: get quota with a non-exist path
     quotaGet = manager.getQuotaUsage("/non-exist-path");
     assertNull(quotaGet);
 
-    // test case2: get quota from an no-quota set path
+    // test case2: get quota from a no-quota set path
     RouterQuotaUsage.Builder quota = new RouterQuotaUsage.Builder()
         .quota(HdfsConstants.QUOTA_RESET)
         .spaceQuota(HdfsConstants.QUOTA_RESET);
@@ -88,7 +88,7 @@ public void testGetQuotaUsage() {
     // it should return null
     assertNull(quotaGet);
 
-    // test case3: get quota from an quota-set path
+    // test case3: get quota from a quota-set path
     quota.quota(1);
     quota.spaceQuota(HdfsConstants.QUOTA_RESET);
     manager.put("/hasQuotaSet", quota.build());
@@ -96,24 +96,24 @@ public void testGetQuotaUsage() {
     assertEquals(1, quotaGet.getQuota());
     assertEquals(HdfsConstants.QUOTA_RESET, quotaGet.getSpaceQuota());
 
-    // test case4: get quota with an non-exist child path
+    // test case4: get quota with a non-exist child path
     quotaGet = manager.getQuotaUsage("/hasQuotaSet/file");
     // it will return the nearest ancestor which quota was set
     assertEquals(1, quotaGet.getQuota());
     assertEquals(HdfsConstants.QUOTA_RESET, quotaGet.getSpaceQuota());
 
-    // test case5: get quota with an child path which its parent
+    // test case5: get quota with a child path which its parent
     // wasn't quota set
     quota.quota(HdfsConstants.QUOTA_RESET);
     quota.spaceQuota(HdfsConstants.QUOTA_RESET);
     manager.put("/hasQuotaSet/noQuotaSet", quota.build());
-    // here should returns the quota of path /hasQuotaSet
+    // here should return the quota of path /hasQuotaSet
     // (the nearest ancestor which quota was set)
     quotaGet = manager.getQuotaUsage("/hasQuotaSet/noQuotaSet/file");
     assertEquals(1, quotaGet.getQuota());
     assertEquals(HdfsConstants.QUOTA_RESET, quotaGet.getSpaceQuota());
 
-    // test case6: get quota with an child path which its parent was quota set
+    // test case6: get quota with a child path which its parent was quota set
     quota.quota(2);
     quota.spaceQuota(HdfsConstants.QUOTA_RESET);
     manager.put("/hasQuotaSet/hasQuotaSet", quota.build());

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterRPCMultipleDestinationMountTableResolver.java

@@ -511,7 +511,7 @@ public void testIsMultiDestDir() throws Exception {
    */
   @Test
   public void testSnapshotPathResolution() throws Exception {
-    // Create a mount entry with non isPathAll order, so as to call
+    // Create a mount entry with non isPathAll order, to call
     // invokeSequential.
     Map<String, String> destMap = new HashMap<>();
     destMap.put("ns0", "/tmp_ns0");

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterRpcMultiDestination.java

@@ -75,7 +75,7 @@
 import org.junit.Test;
 
 /**
- * The the RPC interface of the {@link getRouter()} implemented by
+ * The RPC interface of the {@link getRouter()} implemented by
  * {@link RouterRpcServer}.
  */
 public class TestRouterRpcMultiDestination extends TestRouterRpc {

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/security/token/TestZKDelegationTokenSecretManagerImpl.java

@@ -110,7 +110,7 @@ public void testMultiNodeTokenRemovalShortSyncWithoutWatch()
     conf.setBoolean(ZK_DTSM_TOKEN_WATCHER_ENABLED, false);
     // make sync quick
     conf.setInt(ZK_DTSM_ROUTER_TOKEN_SYNC_INTERVAL, 3);
-    // set the renew window and removal interval to be a
+    // set the renewal window and removal interval to be a
     // short time to trigger the background cleanup
     conf.setInt(RENEW_INTERVAL, 10);
     conf.setInt(REMOVAL_SCAN_INTERVAL, 10);
@@ -170,7 +170,7 @@ public void testMultiNodeTokenRemovalLongSyncWithoutWatch()
     conf.setBoolean(ZK_DTSM_TOKEN_WATCHER_ENABLED, false);
     // make sync quick
     conf.setInt(ZK_DTSM_ROUTER_TOKEN_SYNC_INTERVAL, 20);
-    // set the renew window and removal interval to be a
+    // set the renewal window and removal interval to be a
     // short time to trigger the background cleanup
     conf.setInt(RENEW_INTERVAL, 10);
     conf.setInt(REMOVAL_SCAN_INTERVAL, 10);

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/store/TestStateStoreMembershipState.java

@@ -186,7 +186,7 @@ public void testRegistrationMajorityQuorum()
     // 1) ns0:nn0 - Standby (newest)
     // 2) ns0:nn0 - Active (oldest)
     // 3) ns0:nn0 - Active (2nd oldest)
-    // 4) ns0:nn0 - Active (3nd oldest element, newest active element)
+    // 4) ns0:nn0 - Active (3rd oldest element, newest active element)
     // Verify the selected entry is the newest majority opinion (4)
     String ns = "ns0";
     String nn = "nn0";

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/store/driver/TestStateStoreDriverBase.java

@@ -556,7 +556,7 @@ private static Map<String, Class<?>> getFields(BaseRecord record) {
   }
 
   /**
-   * Get the type of a field.
+   * Get the type of field.
    *
    * @param fieldName
    * @return Field type
@@ -601,7 +601,7 @@ private static Method locateGetter(BaseRecord record, String fieldName) {
   }
 
   /**
-   * Expands a data object from the store into an record object. Default store
+   * Expands a data object from the store into a record object. Default store
    * data type is a String. Override if additional serialization is required.
    *
    * @param data Object containing the serialized data. Only string is