public class ProducerConsumer {    public static void main(String[] args) {        SyncStack ss = new SyncStack();        Producer p = new Producer(ss);        Consumer c = new Consumer(ss);        new Thread(p).start();        new Thread(c).start();    }}class WoTou {    int id;    WoTou(int id) {        this.id = id;    }    public String toString() {        return "WoTou : " + id;    }}class SyncStack {    int index = 0;    WoTou[] arrWT = new WoTou[6];    public synchronized void push(WoTou wt) {        while (index == arrWT.length) {            try {                this.wait();            } catch (InterruptedException e) {                e.printStackTrace();            }        }        this.notifyAll();        arrWT[index] = wt;        index++;    }    public synchronized WoTou pop() {        while (index == 0) {            try {                this.wait();            } catch (InterruptedException e) {                e.printStackTrace();            }        }        this.notifyAll();        index--;        return arrWT[index];    }}class Producer implements Runnable {    SyncStack ss = null;    Producer(SyncStack ss) {        this.ss = ss;    }    public void run() {        for (int i = 0; i < 20; i++) {            WoTou wt = new WoTou(i);            ss.push(wt);            System.out.println("生产了：" + wt);            try {                Thread.sleep((int) (Math.random() * 200));            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }}class Consumer implements Runnable {    SyncStack ss = null;    Consumer(SyncStack ss) {        this.ss = ss;    }    public void run() {        for (int i = 0; i < 20; i++) {            WoTou wt = ss.pop();            System.out.println("消费了: " + wt);            try {                Thread.sleep((int) (Math.random() * 1000));            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }}