package com.example.demo.thread;

/**
 * @projectName: demo
 * @package: com.example.demo.thread
 * @className: TestJoin
 * @author:
 * @description:
 * @date: 2021/11/26 18:40
 */
public class TestJoin {

    public static void main(String[] args) throws InterruptedException {
        MyJoin myJoin = new MyJoin();
        Thread thread = new Thread(myJoin);
        thread.start();

        for (int i = 0; i < 1000; i++) {
            if (i == 100) {
                thread.join();
            }
            System.out.println("主线程" + i + "次");
        }
    }

}

class MyJoin implements Runnable {

    @Override
    public void run() {
        for (int i = 0; i < 100; i++) {
            System.out.println("jion线程" + i + "次");
        }
    }
}

最开始主线程和Myjoin全在执行

满足条件后优先执行MyJoin

MyJoin执行完成后再执行主线程