code: public void stop()
    {
      synchronized (startStopLock) {
        running = false;
        taskStatusChecker.shutdownNow();
  
        if (numRunningTasks > 0) {
          final Iterator<MonitorEntry> iterator = runningTasks.values().iterator();
          while (iterator.hasNext()) {
            final MonitorEntry entry = iterator.next();
            iterator.remove();
            final String taskId = entry.runningTask.getId();
            log.info("Request to kill subtask[%s]", taskId);
            indexingServiceClient.killTask(taskId);
            numRunningTasks--;
            numKilledTasks++;
          }
  
          if (numRunningTasks > 0) {
            log.warn(
                "Inconsistent state: numRunningTasks[%d] is still not zero after trying to kill all running tasks.",
                numRunningTasks
            );
          }
        }
  
        log.info("Stopped taskMonitor");
      }
    }
docs: Stop task monitoring and kill all running tasks.