HBASE-27426 - Fix ZKWatcher shutdown seqence to avoid InterruptExcept… (

#4829)

Signed-off-by: Andrew Purtell <apurtell@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>
Co-authored-by: Victor Li <victor.li@salesforce.com>

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKWatcher.java

@@ -735,12 +735,20 @@ public void interruptedExceptionNoThrow(InterruptedException ie, boolean throwLa
    */
   @Override
   public void close() {
+    zkEventProcessor.shutdown();
     try {
-      recoverableZooKeeper.close();
+      if (!zkEventProcessor.awaitTermination(15, TimeUnit.SECONDS)) {
+        LOG.warn("ZKWatcher event processor has not finished to terminate.");
+        zkEventProcessor.shutdownNow();
+      }
     } catch (InterruptedException e) {
       Thread.currentThread().interrupt();
     } finally {
-      zkEventProcessor.shutdownNow();
+      try {
+        recoverableZooKeeper.close();
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+      }
     }
   }