SingleThreadExecutor中java.util.concurrent.RejectedExecutionException的可能原因是什么

Question

我在单例中创建以下执行程序：

   final private ExecutorService executor = Executors.newSingleThreadExecutor(new ThreadFactory() {
        final ThreadFactory delegate = Executors.defaultThreadFactory();
        public Thread newThread(Runnable paramAnonymousRunnable) { 
            Thread localThread =      this.delegate.newThread(paramAnonymousRunnable);
            localThread.setName("MyTask-" + localThread.getName());
            localThread.setDaemon(XXX.this.daemonThread);
            return localThread;
        }
    });

在程序执行期间，对单例的这种方法有很多调用。调用是在不同的线程中完成的，也许是在同一时间完成的。

private void send(final String paramString) {
  try {
      this.executor.execute(new Runnable() {
          public void run() {
              //DO some interesting stuff
          }
      });
  } catch (Exception localException) {
    this.handler.handle(localException);
  }

}

在某些时候，以下堆栈开始出现：

java.util.concurrent.RejectedExecutionException
        at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:1774)
        at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:768)
        at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:656)
        at java.util.concurrent.Executors$DelegatedExecutorService.execute(Executors.java:589)
        at XXXXX.send(XXXX.java:269)

为什么jvm会抛出这样的异常？

singleThreadExecutor由LinkedBlockingQueue（）支持。 线程池没有关闭。

有关信息，jvm是oracle jdk 1.6。单身是用弹簧创造的。从java.util.concurrent.Executors复制：

   public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory) {
       return new FinalizableDelegatedExecutorService
           (new ThreadPoolExecutor(1, 1,
                                0L, TimeUnit.MILLISECONDS,
                                new LinkedBlockingQueue<Runnable>(),
                                threadFactory));
   }

Answer 1

execute投掷RejectedExecutionException有两个原因

1. 队列已满，您无法再添加任何线程
2. ThreadPool已经关闭

由于您使用的是LinkedBlockingQueue，我发现这种情况的唯一方法是关闭池。

Answer 2

您可能在调用executor.shutdown()后提交了任务。通常他们会停止执行者

    executor.shutdown();
    executor.awaitTermination(10, TimeUnit.MINUTES);

Answer 3

也许您应该使用线程池而不是使用单个执行程序。

    executor = new java.util.concurrent.ThreadPoolExecutor(30, 30, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(), new ThreadFactory() {
        final AtomicInteger threadNumber = new AtomicInteger( 1 );
        @Override
        public Thread newThread(Runnable r) {
            return new Thread(r, "Thread No : " + threadNumber.getAndIncrement());
        }
    });

Answer 4

线程不可用于执行给定任务。没有链接的块队列到que任务。