### Question:
IoTDBThreadPoolFactory { public static ScheduledExecutorService newSingleThreadScheduledExecutor(String poolName) { return Executors.newSingleThreadScheduledExecutor(new IoTThreadFactory(poolName)); }  static ExecutorService newFixedThreadPool(int nthreads, String poolName); static ExecutorService newFixedThreadPool(int nthreads, String poolName,
      Thread.UncaughtExceptionHandler handler); static ExecutorService newSingleThreadExecutor(String poolName); static ExecutorService newSingleThreadExecutor(String poolName,
      Thread.UncaughtExceptionHandler handler); static ExecutorService newCachedThreadPool(String poolName); static ExecutorService newCachedThreadPool(String poolName,
      Thread.UncaughtExceptionHandler handler); static ScheduledExecutorService newSingleThreadScheduledExecutor(String poolName); static ScheduledExecutorService newSingleThreadScheduledExecutor(String poolName,
      Thread.UncaughtExceptionHandler handler); static ScheduledExecutorService newScheduledThreadPool(int corePoolSize, String poolName); static ScheduledExecutorService newScheduledThreadPool(int corePoolSize, String poolName,
      Thread.UncaughtExceptionHandler handler); static ExecutorService createJDBCClientThreadPool(Args args, String poolName); static ExecutorService createJDBCClientThreadPool(Args args, String poolName,
      Thread.UncaughtExceptionHandler handler);  }### Answer:
@Test public void testNewSingleThreadScheduledExecutor() throws InterruptedException { String reason = "NewSingleThreadScheduledExecutor"; Thread.UncaughtExceptionHandler handler = new TestExceptionHandler(reason); int threadCount = 1; latch = new CountDownLatch(threadCount); ScheduledExecutorService exec = IoTDBThreadPoolFactory .newSingleThreadScheduledExecutor(POOL_NAME, handler); for (int i = 0; i < threadCount; i++) { Runnable task = new TestThread(reason); ScheduledFuture<?> future = exec.scheduleAtFixedRate(task, 0, 1, TimeUnit.SECONDS); try { future.get(); } catch (ExecutionException e) { assertEquals(reason, e.getCause().getMessage()); count.addAndGet(1); latch.countDown(); } } try { latch.await(); assertEquals(count.get(), threadCount); } catch (InterruptedException E) { fail(); } }