有些方法有timeout参数, 使用这些方法将让线程进入timed waiting状态. 当计时结束时恢复. 这些方法包括: Thread.sleep and the timed versions of Object.wait, Thread.join, Lock.tryLock, and Condition.await
Terminated Threads
It dies a natural death because the run method exits normally. (包括使用interrupt)
It dies abruptly because an uncaught exception terminates the run method