死锁的实例

死锁的实例

package day11_second;

public class DeathLock {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		DeathLocked1 dl1 = new DeathLocked1();
		DeathLocked2 dl2 = new DeathLocked2();
		Thread t1 = new Thread(dl1);
		Thread t2 = new Thread(dl2);
		t1.start();
		t2.start();
	}

}


class Res {
	
	public static Object obj1 = new Object();
	public static Object obj2 = new Object();
}

class DeathLocked1 implements Runnable{

	@Override
	public void run() {
		// TODO Auto-generated method stub
		fun();
	}

	private void fun() {
		// TODO Auto-generated method stub
		synchronized (Res.obj1) {
			try {Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			synchronized (Res.obj2) {
				System.out.println("在obj1中调用obj2");
			}
		}
	}
	
}


class DeathLocked2 implements Runnable{

	@Override
	public void run() {
		// TODO Auto-generated method stub
		fun();
	}

	private void fun() {
		// TODO Auto-generated method stub
		synchronized (Res.obj2) {
			try {Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			synchronized (Res.obj1) {
				System.out.println("在obj2中调用obj1");
			}
		}
	}
	
}

　　当启动线程t1后，执行t1的fun方法，占用o1资源，然后t1休眠确保能够让t2来执行。t2执行fun()方法，占有o2资源。此时就形成了死锁产生的第四个必要条件。即线程t1占有了t2所需的资源，t2占有了t1所需的资源，双方都不释放，即形成死锁。

      http://my.oschina.net/u/1469592/blog/208374