思路:

創(chuàng)建兩個字符串a(chǎn)和b，再創(chuàng)建兩個線程A和B，
讓每個線程都用synchronized鎖住字符串（A先鎖a，再去鎖b；B先鎖b，再鎖a）
如果A鎖住a，B鎖住b，A就沒辦法鎖住b，B也沒辦法鎖住a，這時就陷入了死鎖

public class DeadLock {
    public static String obj1 = "obj1";
    public static String obj2 = "obj2";
    public static void main(String[] args){
        Thread a = new Thread(new Lock1());
        Thread b = new Thread(new Lock2());
        a.start();
        b.start();
    }    
}
class Lock1 implements Runnable{
    @Override
    public void run(){
        try{
            System.out.println("Lock1 running");
            while(true){
                synchronized(DeadLock.obj1){
                    System.out.println("Lock1 lock obj1");
                    // 獲取obj1后先等一會兒，讓Lock2有足夠的時間鎖住obj2
                    Thread.sleep(3000);
                    synchronized(DeadLock.obj2){
                        System.out.println("Lock1 lock obj2");
                    }
                }
            }
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}
class Lock2 implements Runnable{
    @Override
    public void run(){
        try{
            System.out.println("Lock2 running");
            while(true){
                synchronized(DeadLock.obj2){
                    System.out.println("Lock2 lock obj2");
                    Thread.sleep(3000);
                    synchronized(DeadLock.obj1){
                        System.out.println("Lock2 lock obj1");
                    }
                }
            }
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}

打印結(jié)果:

Result.png

原文地址：http://www.cnblogs.com/mudao/p/5867107.html