实例代码：
package test; public class WNDemo { public static void main(String[] args) { Data2 d = new Data2(); new Producer(d).start(); new Consumer(d).start(); } } class Data2 { int i; public void add() { synchronized (this) { i++; if (i % 5 == 0) { notifyAll(); } } } public void sub() { synchronized (this) { try { this.wait(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("Before:" + i); i -= 5; System.out.println("After:" + i); } } } class Consumer extends Thread { Data2 data2; public Consumer(Data2 data2) { this.data2 = data2; } public void run() { while (true) { data2.sub(); } } } class Producer extends Thread { Data2 data2; public Producer(Data2 data2) { this.data2 = data2; } public void run() { while (true) { data2.add(); } } }
