public void testMustNotBeAbleToShutdownGlobalPool() {
   ExecutorService service = AppExecutorUtil.getAppExecutorService();
   try {
     service.shutdown();
     fail();
   } catch (Exception ignored) {
   }
   try {
     service.shutdownNow();
     fail();
   } catch (Exception ignored) {
   }
   try {
     ((ThreadPoolExecutor) service).setThreadFactory(Thread::new);
     fail();
   } catch (Exception ignored) {
   }
   try {
     ((ThreadPoolExecutor) service).setCorePoolSize(0);
     fail();
   } catch (Exception ignored) {
   }
 }
 public void setThreadFactory(ThreadFactory factory) {
   pool.setThreadFactory(factory);
 }