java - 执行线程是否通过同时执行 wait() 和 join() 进入 "waiting"状态？

Question

对于处于 Activity 状态但既不运行也不可运行的线程，有 3 种状态:-

1. sleep
2. 已屏蔽
3. 等待

当线程执行 sleep() 方法时，它会在其参数指定的时间段(例如几毫秒)内从运行状态进入休眠状态。

当一个线程正在等待某个对象上的锁，而该对象由于同步方法或 block 而被其他线程获取时，该线程就会被该线程阻塞。

那么，我们可以说一个线程在其他线程上执行 wait() 时就进入了 WAITING 状态吗？

在某个线程上调用 join() 也是如此。

那么，我们是否可以说 wait()(来自 java.lang.Object)和 join()(来自 java.lang.Thread)都将线程的状态转变为 WAITING？

Answer 1

这在 javadoc of Thread.State 中有描述。 :

public static final Thread.State WAITING

Thread state for a waiting thread. A thread is in the waiting state due to calling one of the following methods:

    Object.wait with no timeout
    Thread.join with no timeout
    LockSupport.park

A thread in the waiting state is waiting for another thread to perform a particular action. For example, a thread that has called Object.wait() on an object is waiting for another thread to call Object.notify() or Object.notifyAll() on that object. A thread that has called Thread.join() is waiting for a specified thread to terminate.