現在有T1、T2、T3三個執行緒，你怎樣保證T2在T1執行完後執行，T3在T2執行完後執行？

public class Main {
    private static void method02() throws InterruptedException {
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                System.out.println(Thread.currentThread().getName() + "執行完成");
            }
        };
        Thread t1 = new Thread(runnable, "t1");
        Thread t2 = new Thread(runnable, "t2");
        Thread t3 = new Thread(runnable, "t3");
            t1.start();
            t1.join();
            t2.start();
            t2.join();
            t3.start();
            t3.join();
    }

    public static void main(String[] args) throws InterruptedException {
        method02();
    }
}

輸出
t1執行完成
t2執行完成
t3執行完成
 

程式執行時間順序：