HBASE-22509 Address findbugs/spotbugs complaints (branch-1.4) (#277)

Signed-off-by: Sean Busbey <busbey@apache.org>

Author: apurtell

hbase-common/src/main/java/org/apache/hadoop/hbase/io/encoding/EncodedDataBlock.java

@@ -255,7 +255,7 @@ public byte[] encodeData() {
       }
       BufferGrabbingByteArrayOutputStream stream = new BufferGrabbingByteArrayOutputStream();
       baos.writeTo(stream);
-      this.dataBlockEncoder.endBlockEncoding(encodingCtx, out, stream.ourBytes);
+      this.dataBlockEncoder.endBlockEncoding(encodingCtx, out, stream.toByteArray());
     } catch (IOException e) {
       throw new RuntimeException(String.format(
           "Bug in encoding part of algorithm %s. " +
@@ -272,6 +272,11 @@ private static class BufferGrabbingByteArrayOutputStream extends ByteArrayOutput
     public synchronized void write(byte[] b, int off, int len) {
       this.ourBytes = b;
     }
+
+    @Override
+    public synchronized byte[] toByteArray() {
+      return ourBytes;
+    }
   }
 
   @Override

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/metrics2/lib/MetricsExecutorImpl.java

@@ -48,7 +48,7 @@ public void stop() {
 
   private enum ExecutorSingleton {
     INSTANCE;
-    private final ScheduledExecutorService scheduler = new ScheduledThreadPoolExecutor(1,
+    private transient final ScheduledExecutorService scheduler = new ScheduledThreadPoolExecutor(1,
         new ThreadPoolExecutorThreadFactory("HBase-Metrics2-"));
   }
 

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java

@@ -7963,7 +7963,9 @@ public Result append(Append mutate, long nonceGroup, long nonce) throws IOExcept
         for (Map.Entry<Store, List<Cell>> entry: removedCellsForMemStore.entrySet()) {
           entry.getKey().add(entry.getValue());
         }
-        if (we != null) mvcc.complete(we);
+        if (we != null) {
+          mvcc.complete(we);
+        }
       } else if (we != null) {
         mvcc.completeAndWait(we);
       }
@@ -8184,16 +8186,21 @@ private Result doIncrement(Increment increment, long nonceGroup, long nonce) thr
         rowLock.release();
       }
       // if the wal sync was unsuccessful, remove keys from memstore
+      WriteEntry we = walKey != null ? walKey.getWriteEntry() : null;
       if (doRollBackMemstore) {
         for (Map.Entry<Store, List<Cell>> entry: forMemStore.entrySet()) {
           rollbackMemstore(entry.getKey(), entry.getValue());
         }
         for (Map.Entry<Store, List<Cell>> entry: removedCellsForMemStore.entrySet()) {
           entry.getKey().add(entry.getValue());
         }
-        if (walKey != null) mvcc.complete(walKey.getWriteEntry());
+        if (we != null) {
+          mvcc.complete(we);
+        }
       } else {
-        if (walKey != null) mvcc.completeAndWait(walKey.getWriteEntry());
+        if (we != null) {
+          mvcc.completeAndWait(we);
+        }
       }
     }
 

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HStore.java

@@ -2836,10 +2836,14 @@ private void removeCompactedfiles(Collection<StoreFile> compactedfiles)
             // Just close and return
             filesToRemove.add(file);
           } else {
-            LOG.info("Can't archive compacted file " + file.getPath()
+            if (r != null) {
+              LOG.info("Can't archive compacted file " + file.getPath()
                 + " because of either isCompactedAway=" + r.isCompactedAway()
                 + " or file has reference, isReferencedInReads=" + r.isReferencedInReads()
                 + ", refCount=" + r.getRefCount() + ", skipping for now.");
+            } else {
+              LOG.info("Can't archive compacted file " + file.getPath() + ", skipping for now.");
+            }
           }
         } catch (Exception e) {
           LOG.error(