带corePoolSize = 0的ScheduledThreadPoolExecutor导致一个CPU内核上的负载为100％

Question

提供以下配置，ScheduledThreadPoolExecutor每5秒运行一次简单任务：

int corePoolSize = 0;
ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(corePoolSize);

Runnable task = () -> System.out.println("XXX");
executor.scheduleAtFixedRate(task, 5, 5, TimeUnit.SECONDS);

在Oracle
JRE上1.8.0_66，创建了一个线程，该线程ScheduledThreadPoolExecutor不断在一个CPU内核上造成100％的负载。调查线程转储会显示以下堆栈跟踪：

"pool-1-thread-1" - Thread t@10
   java.lang.Thread.State: RUNNABLE
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.poll(ScheduledThreadPoolExecutor.java:809)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

随着corePoolSize = 1仍有池中一个线程。但是，线程基本上始终处于状态TIMED_WAITING，因此处于空闲状态。

是ScheduledThreadPoolExecutor具有corePoolSize = 0已知功能，未经验证的错误配置甚至是错误的行为？

Answer 1

看起来你已经打JDK-8129861已经固定在Java中9.它也可以与JDK-8022642。