有T1、T2、T3三个线程，要求T2在T1执行完后执行，T3在T2执行完后执行(线程顺序执行)

主要考察线程Thread类中join方法，javaAPI中给出join的解释是“等待该线程终止”;

public class ThreadDemo {public static void main(String[] args) throws InterruptedException {Thread T1 = new Thread(new MyThread("春天"));Thread T2 = new Thread(new MyThread("夏天"));Thread T3 = new Thread(new MyThread("秋天"));T1.start();T1.join();T2.start();T2.join();T3.start();T3.join();}
}class MyThread implements Runnable {private final String name;public MyThread(String name) {this.name = name;}public void run() {for (int i = 0; i < 100; i++) {System.out.println(name);}}
}