設定執行緒優先順序：join()

package com.cppdy;

class MyThreadA extends Thread{

    MyThreadB b;
    public MyThreadA(MyThreadB b) {
        this.b=b;
    }
    
    @Override
    public void run() {
        try {
            b.join();
            sleep(1000);
        } catch (Exception e) {
            
        }
        System.out.println(
 
"A子執行緒執行");
    }
    
}

class MyThreadB extends Thread{

    @Override
    public void run() {
        try {
            sleep(1000);
        } catch (Exception e) {
            
        }
        System.out.println("B子執行緒執行");
    }
    
}

public class ThreadDemo4 {

    public static void main(String[] args) throws
 
 Exception{
        MyThreadB mt2 = new MyThreadB();
        MyThreadA mt1 = new MyThreadA(mt2);
        mt1.start();
        mt2.start();
        mt1.join();
        System.out.println("主執行緒執行");
    }

}