class Info {private String name;private String content;private boolean flag;public boolean isFlag() {return flag;}public void setFlag(boolean flag) {this.flag = flag;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getContent() {return content;}public void setContent(String content) {this.content = content;}
}
class Producer implements Runnable {private Info info;public Producer(Info info) {this.info = info;}@Overridepublic void run() {try {Thread.sleep(5000);} catch (InterruptedException e1) {e1.printStackTrace();}boolean flag = false;for (int i = 0; i < 10; i++) {if (!flag) {synchronized (info) {if (info.isFlag()) {try {System.out.println("有产品（MLDN），生产者等待消费....");info.wait();} catch (InterruptedException e) {e.printStackTrace();}}this.info.setName("李兴华");try {Thread.sleep(90);} catch (InterruptedException e) {e.printStackTrace();}this.info.setContent("教学老师 + " + i);flag = true;info.setFlag(true);System.out.println("set()--李兴华&&java讲师 flag="+ info.isFlag());info.notify();}} else {synchronized (info) {if (info.isFlag()) {try {System.out.println("有产品（李兴华），生产者等待消费....");info.wait();} catch (InterruptedException e) {e.printStackTrace();}}this.info.setName("MLDN");try {Thread.sleep(90);} catch (InterruptedException e) {e.printStackTrace();}this.info.setContent("WWW.MLDN.CN + " + i);flag = false;info.setFlag(true);System.out.println("set()--MLDN&&WWW.MLDN.CN flag="+ info.isFlag());info.notify();}}}}
}
class Consumer implements Runnable {private Info info;public Consumer(Info info) {this.info = info;}@Overridepublic void run() {for (int i = 0; i < 10; i++) {try {Thread.sleep(5000);} catch (InterruptedException e) {e.printStackTrace();}synchronized (info) {if (!info.isFlag()) {try {System.out.println("没有产品，等待生产....");info.wait();} catch (InterruptedException e) {e.printStackTrace();}}System.out.print(this.info.getName() + "————>");try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(this.info.getContent() + "--" + i);info.setFlag(false);info.notify();}}}
}
public class Test_producer_consumer {public static void main(String[] args) {Info info = new Info();Producer p = new Producer(info);Consumer c = new Consumer(info);Thread t1 = new Thread(p, "p");Thread t2 = new Thread(c, "c");t1.start();t2.start();}
}

结果有上面2种，第一种，当线程1运行到obj.notify();//a处，线程2被唤醒，线程2进入竞争obj对象的锁池。线程1执行完synchronized代码块后，释放对象锁；如果线程1不再参与对象锁的竞争那么结果2中的情况不会发生；但是结果2发生了，线程1再一次拿到对象锁，然后执行到obj.wait()方法后，释放对象锁，线程1进入阻塞状态，线程2获得对象锁。

这个结果是去掉消费者Thread.sleep(5000);得到的一种结果。2个1出现说明,线程1调用obj.notify()后，线程1再一次参与了对象锁的竞争，并且获得到了。