join——实现线程顺序运行

现在有T1、T2、T3三个线程，你怎样保证T2在T1执行完后执行，T3在T2执行完后执行。

public class Homework01 {    public static void main(String[] args) throws InterruptedException {        Thread t1 = new MyThread("t1");        Thread t2 = new MyThread("t2");        Thread t3 = new MyThread("t3");        t1.start();        t1.join();        t2.start();        t2.join();        t3.start();        t3.join();    }}class MyThread extends Thread{    public MyThread(String string) {        super(string);    }    @Override    public void run() {        for(int i=0;i<10;i++){            System.out.println(Thread.currentThread().getName()+"--"+i);        }    }}