@Override
  public void serviceStop() {
    if (!isShutdown.getAndSet(true)) {
      if (queueLookupFuture != null) {
        queueLookupFuture.cancel(true);
      }
      queueLookupExecutor.shutdownNow();
      executor.shutdownNow();
      LOG.info("Stopped service: " + getName());
    }
  }
Responsible for communicating with various AMs.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/AMReporter.java