线程的六种状态

线程的六种状态

image-20200904134354414

情况1 New -> Runnable

当调用t.start()方法时,由New -> Runnable

情况2 Runnable <–> Waiting

t线程用synchronized(obj)获取了对象锁后

  • 调用obj.wait()方法时,t线程从Runnable –> Waiting
  • 调用obj.notify(),obj.notifyAll(),t.interrupt()时:
    • 竞争锁成功,t线程从Waiting –> Runnable
    • 竞争锁失败,t线程从Waiting –> Blocked

情况3 Runnable < – > Waiting

  • 当线程调用t.join()方法时,当前线程从Runnable –> Waiting
    • 注意是当前线程在t线程对象的监视器上等待
  • t线程运行结束,或调用了当前线程的interrupt()时,当前线程从Waiting –> Runnable

情况4 Runnable < – > Waiting

  • 当前线程调用lockSupport.park()方法会让当前线程从Runnable –> Waiting
  • 调用LockSupport.unpark(目标线程)或调用了线程的interrupt(),会让目标线程从Waiting –> Runnable

情况5 Runnable < –>Timed_Waiting

线程synchronized(obj)获取了对象锁后

  • 调用obj.wait(long n)方法时,t线程从Runnable –> Time_Waiting
  • t线程等待时间超过了n毫秒,或调用obj.notify(), obj.notifyAll(), t.interrupt()时
    • 竞争锁成功,t线程从Time_Waiting –> Runnable
    • 竞争锁失败,t线程从Time_Waiting –> Blocked

情况6 Runnable < – > Time_Waiting

  • 当线程调用t.join(long n)方法时,当前线程从Runnable –> Waiting
    • 注意是当前线程在t线程对象的监视器上等待
  • t线程运行结束,或调用了当前线程的interrupt()时,当前线程从Waiting –> Runnable

情况7 Runnable < – > Time_Waiting

  • 当前线程调用了Thread.sleep(long n),当前线程从Runnable –> Timed_Waiting
  • 当前线程等待时间超过了n毫秒,当前线程从Timed_Waiting –> Runnable

情况8 Runnable < – > Time_Waiting

  • 当前线程调用了LockSupport.parkNanos(long nanos)或LockSupport.parkUntil(long millis)时,当前线程从Runnable –> Timed_Waiting
  • 调用LockSupport.unpark(目标线程)或调用了线程的interrupt(),或是等待超时,会让目标线程从Timed_Waiting –> Runnable

情况9 Runnable < – > Blocked

  • t线程用synchronized(obj)获取了对象锁时如果竞争失败,从Runnable –> Blocked
  • 持obj锁线程的同步代码块执行完毕,会唤醒该对象上所有的Blocked的线程重新竞争,如果其中t线程竞争成功,从Blocked –> Runnable,其他失败的线程仍然Blocked

情况10 Runnable < – > Terminated

当前线程所有代码运行完毕,进入Terminated

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Categories:

Concurrent   Java