wait, notify, notifyAll and synchronized --
Object.notify()的API是这样的: Object.notify Class Overview | Class Members | This Package | All Packages Syntax public final native void notify() Description Wakes up a single thread that is waiting on this object's monitor. A thread waits on an object's monitor by calling one of the wait methods. This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways: By executing a synchronized instance method of that object. By executing the body of a synchronized statement that synchronizes on the object.