死锁

/**
 * 死锁问题，在设计程序时就应该避免双方相互持有对方的锁的情况
 * @author alienware
 *
 */
public class DeadLock implements Runnable{


private String tag;
private static Object lock1 = new Object();
private static Object lock2 = new Object();

public void setTag(String tag){
this.tag = tag;
}

@Override
public void run() {
if(tag.equals("a")){
synchronized (lock1) {
try {
System.out.println("当前线程 : "  + Thread.currentThread().getName() + " 进入lock1执行");
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (lock2) {
System.out.println("当前线程 : "  + Thread.currentThread().getName() + " 进入lock2执行");
}
}
}
if(tag.equals("b")){
synchronized (lock2) {
try {
System.out.println("当前线程 : "  + Thread.currentThread().getName() + " 进入lock2执行");
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (lock1) {
System.out.println("当前线程 : "  + Thread.currentThread().getName() + " 进入lock1执行");
}
}
}
}

public static void main(String[] args) {

DeadLock d1 = new DeadLock();
d1.setTag("a");
DeadLock d2 = new DeadLock();
d2.setTag("b");
 
Thread t1 = new Thread(d1, "t1");
Thread t2 = new Thread(d2, "t2");
 
t1.start();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
t2.start();
}




}