public class RunnableTest2 {

     public static Object obj1 = new Object();

     public static Object obj2 = new Object();

     private MyThread1 t1 = new MyThread1();

     private MyThread2 t2 = new MyThread2();

     public static void main(String[] args) {

         RunnableTest2 tr = new RunnableTest2();

         tr.t1.start();

         tr.t2.start();

     }

 }

 class MyThread1 extends Thread {

     @Override

     public void run() {

         System.out.println(Thread.currentThread()+"锁定了obj1，过2秒锁定obj2去");

         synchronized (RunnableTest2.obj1) {

             try {

                 Thread.sleep(2000);

                 synchronized (RunnableTest2.obj2) {

                     System.out.println("1");

                 }

             } catch (InterruptedException e) {

                 e.printStackTrace();

             }

         }

     }

 }

 class MyThread2 extends Thread {

     @Override

     public void run() {

             System.out.println(Thread.currentThread()+"锁定了obj2，过2秒锁定obj1去");

             synchronized (RunnableTest2.obj2) {

                 try {

                     Thread.sleep(2000);

                     synchronized (RunnableTest2.obj1) {

                         System.out.println("2");

                     }

                 } catch (InterruptedException e) {

                     // TODO Auto-generated catch block

                     e.printStackTrace();

                 }

             }

     }

 }

打印结果：

Thread[Thread-0,5,main]锁定了obj1，过2秒锁定obj2去
Thread[Thread-1,5,main]锁定了obj2，过2秒锁定obj1去