关于java线程死锁。有问题

Question

[code="java"]
public class DeadLockTest implements Runnable
{
private int flag = 1;

protected Object o1 = new Object();

protected Object o2 = new Object();
/**
 * run方法
 */
@Override
public void run()
{
    System.out.println("flag = " + flag);

    if(flag == 1)
    {
        synchronized (o1)
        {
            try
            {
                System.out.println("o1 is locked");
                Thread.sleep(500);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
        }
        System.out.println("release o1");
        synchronized (o2)
        {
            System.out.println("1");
        }
    }

    if(flag == 0)
    {
        synchronized (o2)
        {
            try
            {
                System.out.println("o2 is locked");
                Thread.sleep(1000);
            }
            catch (InterruptedException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        System.out.println("release o2");
        synchronized (o1)
        {
            System.out.println("0");
        }
    }

}

/**
 * main函数
 * @author kf56385
 * @param args
 */
public static void main(String[] args)
{
    DeadLockTest d1 = new DeadLockTest();
    d1.flag = 1;

    DeadLockTest d2 = new DeadLockTest();
    d2.flag = 0;

    Thread t1 = new Thread(d1);
    Thread t2 = new Thread(d2);

    t1.start();
    t2.start();
}

[/code]

按照网上写的例子，可是运行时并没有发生死锁，以下是控制台输出：
flag = 1
o1 is locked
flag = 0
o2 is locked
release o1
1
release o2
0
很奇怪，在release o1之后，要输出"1"这个值的时候 o2还是被锁住的。怎么还会有输出呢？望指教

Answer 1

上面的代码没有死锁问题，改成这样就会死锁，为了让你肉体感觉明显，加大了sleep的参数：
[code]
if (flag == 1) {
synchronized (o1) {
try {
System.out.println("o1 is locked");
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (o2) {
System.out.println("1");
}
}
}

    if (flag == 0) {
        synchronized (o2) {
            try {
                System.out.println("o2 is locked");
                Thread.sleep(10000000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            synchronized (o1) {
                System.out.println("0");
            }

        }
    }

[/code]