一个死锁的示例代码

可以看到，控制台什么都没有输出，所以是发生了死锁。

public class DeadLock {
	
	public static void main(String[] args) {
		DeadLockThread deadLock1=new DeadLockThread(true);
		DeadLockThread deadLock2=new DeadLockThread(false);
		Thread t1=new Thread(deadLock1);
		Thread t2=new Thread(deadLock2);
		t1.start();
		t2.start();
	}
	
}

class DeadLockThread implements Runnable{
	boolean flag;
	static Object o1=new Object();//这里必须是静态变量，否则加锁就不是在同一个对象上加锁了
	static Object o2=new Object();	
	
	public DeadLockThread(boolean flag){
		this.flag=flag;
	}

	public void run() {
		if(flag){
			synchronized(o1){
				try{
					Thread.sleep(100);
				}
				catch(InterruptedException e){
					e.printStackTrace();
				}
				synchronized(o2){//要放在o1临界区内，因为要保持o1的锁，申请o2的锁
					System.out.println("I am not dead lock!");
				}
			}			
		}
		else{
			synchronized(o2){
				try{
					Thread.sleep(100);
				}
				catch(InterruptedException e){
					e.printStackTrace();
				}
				synchronized(o1){//此处类似，保持o2的锁，申请o1的锁
					System.out.println("I am not dead lock, too.");
				}
			}			
		}
	}
	
}