@Override
    public void onFailure(Throwable t) {
      LOG.error("Wait queue scheduler worker exited with failure!", t);
      Thread.getDefaultUncaughtExceptionHandler().uncaughtException(Thread.currentThread(), t);
    }
Worker that takes tasks from wait queue and schedule it for execution.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/TaskExecutorService.java