as per @itaiy suggested will close then try to connect. (apache#3669)

* as per @itaiy suggested will close then try to connect.

* use close instead of flush

* git fix comments

* break the loop in case of interrupted

extensions-contrib/graphite-emitter/src/main/java/io/druid/emitter/graphite/GraphiteEmitter.java

@@ -136,16 +136,14 @@ public void emit(Event event)
 
   private class ConsumerRunnable implements Runnable
   {
-    private PickledGraphite pickledGraphite = new PickledGraphite(
-        graphiteEmitterConfig.getHostname(),
-        graphiteEmitterConfig.getPort(),
-        graphiteEmitterConfig.getBatchSize()
-    );
-
     @Override
     public void run()
     {
-      try {
+      try (PickledGraphite pickledGraphite = new PickledGraphite(
+          graphiteEmitterConfig.getHostname(),
+          graphiteEmitterConfig.getPort(),
+          graphiteEmitterConfig.getBatchSize()
+      )) {
         if (!pickledGraphite.isConnected()) {
           log.info("trying to connect to graphite server");
           pickledGraphite.connect();
@@ -174,12 +172,16 @@ public void run()
             log.error(e, e.getMessage());
             if (e instanceof InterruptedException) {
               Thread.currentThread().interrupt();
+              break;
             } else if (e instanceof SocketException) {
+              // This is antagonistic to general Closeable contract in Java,
+              // it is needed to allow re-connection in case of the socket is closed due long period of inactivity
+              pickledGraphite.close();
+              log.warn("Trying to re-connect to graphite server");
               pickledGraphite.connect();
             }
           }
         }
-        pickledGraphite.flush();
       }
       catch (Exception e) {
         log.error(e, e.getMessage());