HBASE-20744 Address FindBugs warnings in branch-1

minor fix

Signed-off-by: tedyu <yuzhihong@gmail.com>

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

@@ -255,7 +255,7 @@ public class EncodedDataBlock {
       }
       BufferGrabbingByteArrayOutputStream stream = new BufferGrabbingByteArrayOutputStream();
       baos.writeTo(stream);
-      this.dataBlockEncoder.endBlockEncoding(encodingCtx, out, stream.ourBytes);
+      this.dataBlockEncoder.endBlockEncoding(encodingCtx, out, stream.getOurBytes());
     } catch (IOException e) {
       throw new RuntimeException(String.format(
           "Bug in encoding part of algorithm %s. " +
@@ -268,6 +268,10 @@ public class EncodedDataBlock {
   private static class BufferGrabbingByteArrayOutputStream extends ByteArrayOutputStream {
     private byte[] ourBytes;
 
+    private synchronized byte[] getOurBytes() {
+      return ourBytes;
+    }
+
     @Override
     public synchronized void write(byte[] b, int off, int len) {
       this.ourBytes = b;

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

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

hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/RegionServerQuotaManager.java

@@ -190,21 +190,10 @@ public class RegionServerQuotaManager {
           + e.getMessage());
       // Depending on whether we are supposed to throw a retryable IO exeption or not, choose
       // the correct exception type to (re)throw
-      if (e instanceof ThrottlingException) {
-        if (useRetryableThrottlingException) {
-          throw new RpcThrottlingException(e.getMessage());
-        } else {
-          throw e;
-        }
-      } else if (e instanceof RpcThrottlingException) {
-        if (useRetryableThrottlingException) {
-          throw e;
-        } else {
-          throw new ThrottlingException(e.getMessage());
-        }
-      } else {
-        LOG.warn("Unexpected exception from quota check", e);
+      if (useRetryableThrottlingException) {
         throw e;
+      } else {
+        throw new ThrottlingException(e.getMessage());
       }
     }
     return quota;