diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
index 0e77bfbf5c12..41d13b7d2646 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
@@ -477,8 +477,8 @@ public class HRegionServer extends Thread implements
   protected String useThisHostnameInstead;
 
   /**
-   * @deprecated since 2.4.0 and will be removed in 4.0.0.
-   * Use {@link HRegionServer#UNSAFE_RS_HOSTNAME_DISABLE_MASTER_REVERSEDNS_KEY} instead.
+   * @deprecated since 2.4.0 and will be removed in 4.0.0. Use
+   * {@link HRegionServer#UNSAFE_RS_HOSTNAME_DISABLE_MASTER_REVERSEDNS_KEY} instead.
    * @see <a href="https://issues.apache.org/jira/browse/HBASE-24667">HBASE-24667</a>
    */
   @Deprecated
@@ -727,9 +727,10 @@ protected String getUseThisHostnameInstead(Configuration conf) throws IOExceptio
     String hostname = conf.get(UNSAFE_RS_HOSTNAME_KEY);
     if (conf.getBoolean(UNSAFE_RS_HOSTNAME_DISABLE_MASTER_REVERSEDNS_KEY, false)) {
       if (!StringUtils.isBlank(hostname)) {
-        String msg = UNSAFE_RS_HOSTNAME_DISABLE_MASTER_REVERSEDNS_KEY + " and " + UNSAFE_RS_HOSTNAME_KEY +
-          " are mutually exclusive. Do not set " + UNSAFE_RS_HOSTNAME_DISABLE_MASTER_REVERSEDNS_KEY +
-          " to true while " + UNSAFE_RS_HOSTNAME_KEY + " is used";
+        String msg = UNSAFE_RS_HOSTNAME_DISABLE_MASTER_REVERSEDNS_KEY + " and " +
+          UNSAFE_RS_HOSTNAME_KEY + " are mutually exclusive. Do not set " +
+          UNSAFE_RS_HOSTNAME_DISABLE_MASTER_REVERSEDNS_KEY + " to true while " +
+          UNSAFE_RS_HOSTNAME_KEY + " is used";
         throw new IOException(msg);
       } else {
         return rpcServices.isa.getHostName();
@@ -862,7 +863,8 @@ public boolean registerService(com.google.protobuf.Service instance) {
 
     coprocessorServiceHandlers.put(serviceName, instance);
     if (LOG.isDebugEnabled()) {
-      LOG.debug("Registered regionserver coprocessor executorService: executorService=" + serviceName);
+      LOG.debug("Registered regionserver coprocessor executorService: executorService=" +
+        serviceName);
     }
     return true;
   }
@@ -877,13 +879,15 @@ protected ClusterConnection createClusterConnection() throws IOException {
 
   /**
    * Run test on configured codecs to make sure supporting libs are in place.
-   * @param c
-   * @throws IOException
+   * @param c configuration object
+   * @throws IOException if compression test fails for any regionserver codec
    */
   private static void checkCodecs(final Configuration c) throws IOException {
     // check to see if the codec list is available:
     String [] codecs = c.getStrings(REGIONSERVER_CODEC, (String[])null);
-    if (codecs == null) return;
+    if (codecs == null) {
+      return;
+    }
     for (String codec : codecs) {
       if (!CompressionTest.testCompression(codec)) {
         throw new IOException("Compression codec " + codec +
@@ -1138,9 +1142,15 @@ public void run() {
 
     // Send interrupts to wake up threads if sleeping so they notice shutdown.
     // TODO: Should we check they are alive? If OOME could have exited already
-    if (this.hMemManager != null) this.hMemManager.stop();
-    if (this.cacheFlusher != null) this.cacheFlusher.interruptIfNecessary();
-    if (this.compactSplitThread != null) this.compactSplitThread.interruptIfNecessary();
+    if (this.hMemManager != null) {
+      this.hMemManager.stop();
+    }
+    if (this.cacheFlusher != null) {
+      this.cacheFlusher.interruptIfNecessary();
+    }
+    if (this.compactSplitThread != null) {
+      this.compactSplitThread.interruptIfNecessary();
+    }
 
     // Stop the snapshot and other procedure handlers, forcefully killing all running tasks
     if (rspmHost != null) {
@@ -1247,7 +1257,9 @@ private boolean containsMetaTableRegions() {
   }
 
   private boolean areAllUserRegionsOffline() {
-    if (getNumberOfOnlineRegions() > 2) return false;
+    if (getNumberOfOnlineRegions() > 2) {
+      return false;
+    }
     boolean allUserRegionsOffline = true;
     for (Map.Entry<String, HRegion> e: this.onlineRegions.entrySet()) {
       if (!e.getValue().getRegionInfo().isMetaRegion()) {
@@ -1469,7 +1481,9 @@ private ClusterStatusProtos.ServerLoad buildServerLoad(long reportStartTime, lon
   private String getOnlineRegionsAsPrintableString() {
     StringBuilder sb = new StringBuilder();
     for (Region r: this.onlineRegions.values()) {
-      if (sb.length() > 0) sb.append(", ");
+      if (sb.length() > 0) {
+        sb.append(", ");
+      }
       sb.append(r.getRegionInfo().getEncodedName());
     }
     return sb.toString();
@@ -1577,7 +1591,7 @@ public NamedQueueRecorder getNamedQueueRecorder() {
    * @param c Extra configuration.
    */
   protected void handleReportForDutyResponse(final RegionServerStartupResponse c)
-  throws IOException {
+    throws IOException {
     try {
       boolean updateRootDir = false;
       for (NameStringPair e : c.getMapEntriesList()) {
@@ -1873,7 +1887,7 @@ protected void chore() {
                 this.instance.compactSplitThread.requestCompaction(hr, s,
                     getName() + " requests major compaction; use default priority",
                     Store.NO_PRIORITY,
-                CompactionLifeCycleTracker.DUMMY, null);
+                    CompactionLifeCycleTracker.DUMMY, null);
               } else {
                 this.instance.compactSplitThread.requestCompaction(hr, s,
                     getName() + " requests major compaction; use configured priority",
@@ -1908,7 +1922,9 @@ private static class PeriodicMemStoreFlusher extends ScheduledChore {
     protected void chore() {
       final StringBuilder whyFlush = new StringBuilder();
       for (HRegion r : this.server.onlineRegions.values()) {
-        if (r == null) continue;
+        if (r == null) {
+          continue;
+        }
         if (r.shouldFlush(whyFlush)) {
           FlushRequester requester = server.getFlushRequester();
           if (requester != null) {
@@ -2012,7 +2028,7 @@ private void startServices() throws IOException {
     // Health checker thread.
     if (isHealthCheckerConfigured()) {
       int sleepTime = this.conf.getInt(HConstants.HEALTH_CHORE_WAKE_FREQ,
-      HConstants.DEFAULT_THREAD_WAKE_FREQUENCY);
+        HConstants.DEFAULT_THREAD_WAKE_FREQUENCY);
       healthCheckChore = new HealthCheckChore(sleepTime, this, getConfiguration());
     }
 
@@ -2502,7 +2518,9 @@ public boolean reportRegionStateTransition(final RegionStateTransitionContext co
                 " after " + pauseTime + "ms delay (Master is coming online...).":
                 " immediately."),
             ioe);
-        if (pause) Threads.sleep(pauseTime);
+        if (pause) {
+          Threads.sleep(pauseTime);
+        }
         tries++;
         if (rssStub == rss) {
           rssStub = null;
@@ -2612,7 +2630,7 @@ public void abort(String reason, Throwable cause) {
   /**
    * Sets the abort state if not already set.
    * @return True if abortRequested set to True successfully, false if an abort is already in
-   * progress.
+   *   progress.
    */
   protected boolean setAbortRequested() {
     return abortRequested.compareAndSet(false, true);
@@ -2689,7 +2707,9 @@ protected void stopServiceThreads() {
     if (this.compactSplitThread != null) {
       this.compactSplitThread.join();
     }
-    if (this.executorService != null) this.executorService.shutdown();
+    if (this.executorService != null) {
+      this.executorService.shutdown();
+    }
     if (this.replicationSourceHandler != null &&
         this.replicationSourceHandler == this.replicationSinkHandler) {
       this.replicationSourceHandler.stopReplicationService();
@@ -2704,8 +2724,7 @@ protected void stopServiceThreads() {
   }
 
   /**
-   * @return Return the object that implements the replication
-   * source executorService.
+   * @return Return the object that implements the replication source executorService.
    */
   @InterfaceAudience.Private
   public ReplicationSourceService getReplicationSourceService() {
@@ -2714,7 +2733,7 @@ public ReplicationSourceService getReplicationSourceService() {
 
   /**
    * @return Return the object that implements the replication
-   * sink executorService.
+   *   sink executorService.
    */
   ReplicationSinkService getReplicationSinkService() {
     return replicationSinkHandler;
@@ -2810,8 +2829,8 @@ protected synchronized ServerName createRegionServerStatusStub(boolean refresh)
   }
 
   /**
-   * @return True if we should break loop because cluster is going down or
-   * this server has been stopped or hdfs has gone bad.
+   * @return True if we should break loop because cluster is going down or this server has been
+   *    stopped or hdfs has gone bad.
    */
   private boolean keepLooping() {
     return !this.stopped && isClusterUp();
@@ -2825,10 +2844,14 @@ private boolean keepLooping() {
    * @throws IOException
    */
   private RegionServerStartupResponse reportForDuty() throws IOException {
-    if (this.masterless) return RegionServerStartupResponse.getDefaultInstance();
+    if (this.masterless) {
+      return RegionServerStartupResponse.getDefaultInstance();
+    }
     ServerName masterServerName = createRegionServerStatusStub(true);
     RegionServerStatusService.BlockingInterface rss = rssStub;
-    if (masterServerName == null || rss == null) return null;
+    if (masterServerName == null || rss == null) {
+      return null;
+    }
     RegionServerStartupResponse result = null;
     try {
       rpcServices.requestCount.reset();
@@ -2906,12 +2929,16 @@ private void closeMetaTableRegions(final boolean abort) {
         if (hri.isMetaRegion()) {
           meta = e.getValue();
         }
-        if (meta != null) break;
+        if (meta != null) {
+          break;
+        }
       }
     } finally {
       this.onlineRegionsLock.writeLock().unlock();
     }
-    if (meta != null) closeRegionIgnoreErrors(meta.getRegionInfo(), abort);
+    if (meta != null) {
+      closeRegionIgnoreErrors(meta.getRegionInfo(), abort);
+    }
   }
 
   /**
@@ -3218,17 +3245,17 @@ public static void main(String[] args) {
    */
   @Override
   public List<HRegion> getRegions(TableName tableName) {
-     List<HRegion> tableRegions = new ArrayList<>();
-     synchronized (this.onlineRegions) {
-       for (HRegion region: this.onlineRegions.values()) {
-         RegionInfo regionInfo = region.getRegionInfo();
-         if(regionInfo.getTable().equals(tableName)) {
-           tableRegions.add(region);
-         }
-       }
-     }
-     return tableRegions;
-   }
+    List<HRegion> tableRegions = new ArrayList<>();
+    synchronized (this.onlineRegions) {
+      for (HRegion region: this.onlineRegions.values()) {
+        RegionInfo regionInfo = region.getRegionInfo();
+        if(regionInfo.getTable().equals(tableName)) {
+          tableRegions.add(region);
+        }
+      }
+    }
+    return tableRegions;
+  }
 
   @Override
   public List<HRegion> getRegions() {
@@ -3402,13 +3429,16 @@ public boolean removeRegion(final HRegion r, ServerName destination) {
       if (closeSeqNum == HConstants.NO_SEQNUM) {
         // No edits in WAL for this region; get the sequence number when the region was opened.
         closeSeqNum = r.getOpenSeqNum();
-        if (closeSeqNum == HConstants.NO_SEQNUM) closeSeqNum = 0;
+        if (closeSeqNum == HConstants.NO_SEQNUM) {
+          closeSeqNum = 0;
+        }
       }
       boolean selfMove = ServerName.isSameAddress(destination, this.getServerName());
       addToMovedRegions(r.getRegionInfo().getEncodedName(), destination, closeSeqNum, selfMove);
       if (selfMove) {
-        this.regionServerAccounting.getRetainedRegionRWRequestsCnt().put(r.getRegionInfo().getEncodedName()
-          , new Pair<>(r.getReadRequestsCount(), r.getWriteRequestsCount()));
+        this.regionServerAccounting.getRetainedRegionRWRequestsCnt().put(
+          r.getRegionInfo().getEncodedName(),
+          new Pair<>(r.getReadRequestsCount(), r.getWriteRequestsCount()));
       }
     }
     this.regionFavoredNodesMap.remove(r.getRegionInfo().getEncodedName());
@@ -3523,7 +3553,7 @@ public void updateRegionFavoredNodesMapping(String encodedRegionName,
    * Return the favored nodes for a region given its encoded name. Look at the
    * comment around {@link #regionFavoredNodesMap} on why we convert to InetSocketAddress[]
    * here.
-   * @param encodedRegionName
+   * @param encodedRegionName the encoded region name.
    * @return array of favored locations
    */
   @Override
@@ -3543,7 +3573,7 @@ private static class MovedRegionInfo {
     MovedRegionInfo(ServerName serverName, long closeSeqNum) {
       this.serverName = serverName;
       this.seqNum = closeSeqNum;
-     }
+    }
 
     public ServerName getServerName() {
       return serverName;
@@ -3560,7 +3590,8 @@ public long getSeqNum() {
    */
   private static final int TIMEOUT_REGION_MOVED = (2 * 60 * 1000);
 
-  private void addToMovedRegions(String encodedName, ServerName destination, long closeSeqNum, boolean selfMove) {
+  private void addToMovedRegions(String encodedName, ServerName destination,
+    long closeSeqNum, boolean selfMove) {
     if (selfMove) {
       LOG.warn("Not adding moved region record: " + encodedName + " to self.");
       return;
@@ -3581,7 +3612,7 @@ public MovedRegionInfo getMovedRegion(String encodedRegionName) {
 
   @InterfaceAudience.Private
   public int movedRegionCacheExpiredTime() {
-        return TIMEOUT_REGION_MOVED;
+    return TIMEOUT_REGION_MOVED;
   }
 
   private String getMyEphemeralNodePath() {
@@ -3609,8 +3640,8 @@ CoprocessorServiceResponse execRegionServerService(
       String serviceName = call.getServiceName();
       com.google.protobuf.Service service = coprocessorServiceHandlers.get(serviceName);
       if (service == null) {
-        throw new UnknownProtocolException(null, "No registered coprocessor executorService found for " +
-            serviceName);
+        throw new UnknownProtocolException(null,
+          "No registered coprocessor executorService found for " + serviceName);
       }
       com.google.protobuf.Descriptors.ServiceDescriptor serviceDesc =
           service.getDescriptorForType();