package com.cn.commodity.config;

public class Sync {

    public synchronized void test() {

        System.out.println("test start");

        try {

            Thread.sleep(5000);

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

        System.out.println("test end");

    }

}

package com.cn.commodity.config;

public class MyThread2 extends Thread {

    public Sync sync;

    MyThread2(Sync sync) {

        this.sync = sync;

    }

    @Override

    public void run() {

        System.out.println("hi....");

        sync.test();

    }

    public static void main(String[] args) {

        Sync sync = new Sync();

        for (int i = 0; i < 3; ++i) {

            Thread thread = new MyThread2(sync);

            thread.start();

        }

    }

}