notifyall

The root Object class includes some special methods for communicating across threads& wait(), notify(), and notifyAll().

根类Object包含某些特殊的方法，用来在线程的wait（）、notify（）和notifyAll（）之间进行通信。

The wait() method tells the current thread to go into an inactive state and wait for another thread to call notifyAll() on that object.

wait（）方法将通知当前线程进入非活动状态，并等待另一个线对该对象调用notifyAll（）。

Careful: replacing the notifyAll() with notify() solves the problem in this scenario but will fail on others!)

注意：用notify（）取代notifyAll（）能解决此情形中的问题，但是在其他情形中将会失败！

When an external process calls the Bucket's ( also synchronized) flush() method, a notifyAll() is sent, thereby waking up all blocking processes.

当外部进程调用Bucket的（也是同步的）flush（）方法时，就发送一个notifyAll（），唤醒所有受阻塞的线程。