Java死锁的简单例子

Java死锁的简单例子

两个线程互相占有对方需要的资源而不释放，便形成了死锁。

代码如下：
Program.java

/**
 * 程序类
 * @author michael
 *
 */
public class Program implements Runnable {

//两个静态的资源
public static Object obj1 = new Object();
public static Object obj2 = new Object();

//标志位
public int flag = 1;    //1 or 2

@Override
public void run() {

if(flag == 1) {
synchronized (obj1) {
                System.out.println("flag: " + flag + ", 锁住了资源obj1");
try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
// TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println("flag: " + flag + ", 等待获取资源obj2");
synchronized (obj2) {
                    System.out.println("flag: " + flag + ", 获得资源obj2");
                }
            }
        } else if(flag == 2) {
synchronized (obj2) {
                System.out.println("flag: " + flag + ", 锁住了资源obj2");
try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
// TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println("flag: " + flag + ", 等待获取资源obj1");
synchronized (obj1) {
                    System.out.println("flag: " + flag + ", 获得资源obj1");
                }
            }
        }   
    }

}

DeadLock.java

DeadLock.java
/**
 * 死锁测试.
 * @author michael
 *
 */
public class DeadLock {

public static void main(String[] args) {

        Program p1 = new Program();
        Program p2 = new Program();
        p1.flag = 1;
        p2.flag = 2;

new Thread(p1).start();
new Thread(p2).start();

    }

}

控制台结果：