public void executeTask(final Runnable r) {
        if (!isStopped()) {
            this.scheduledExecutorService.execute(r);
        } else {
            logger.warn("PullMessageServiceScheduledThread has shutdown");
        }
    }
@Test
    public void testExecuteTask() {
        Runnable runnable = mock(Runnable.class);
        pullMessageService.executeTask(runnable);
        pullMessageService.makeStop();
        pullMessageService.executeTask(runnable);
        verify(executorService, times(1)).execute(any(Runnable.class));
    }