编写一个死锁的程序

public class DeadLock implements Runnable{
    
    int flag = 1;
    static Object o1 = new Object();
    static Object o2 = new Object();
    
    public static void main(String[] args){
        DeadLock d1 = new DeadLock();
        DeadLock d2 = new DeadLock();
        d2.flag = 0;
        Thread t1 = new Thread(d1);
        Thread t2 = new Thread(d2);
        t1.start();
        t2.start();
    }
    
    public void run(){
        if(flag == 1){
            synchronized(o1){
                try{
                    Thread.sleep(5000);
                } catch(InterruptedException e){
                    e.printStackTrace();
                }
                synchronized(o2){
                    System.out.println("1");
                }
            }
        }
        
        if(flag == 0){
            synchronized(o2){
                try{
                    Thread.sleep(5000);
                } catch(InterruptedException e){
                    e.printStackTrace();
                }
                synchronized(o1){
                    System.out.println("0");
                }
            }
        }
    }
    
}