java 多线程-join插队

public class n {

public static void main(String[]args) throws InterruptedException
{
    Thread t =new Thread(()-> {
        for(int i=0;i<5;i++)
        {
            System.out.println("a"+i);
        }
    });
    t.start();

    for(int i=0;i<5;i++)
    {
        if(i%2==0)
        {
            t.join();//插队，此时main主线程被阻塞，插队线程执行完所有步骤再执行main
        }
        System.out.println("b"+i);
    }

}

}

例二：

public class n {

public static void main(String[]args) throws InterruptedException
{
    new Thread(new father()).start();

}

}

class father extends Thread{
public void run()
{
    System.out.println("想抽象，发现没了");
    System.out.println("让儿子买中华");
    Thread t=new Thread(new son());
    t.start(); //不行，各走各的逻辑错误，再加入join先执行完son，再执行father剩下的
    try {
        t.join();
    } catch (InterruptedException e) {

        e.printStackTrace();
    }
    System.out.println("接过烟");
}
}

class son extends Thread{
public void run()
{
    System.out.println("拿钱");
    System.out.println("路边玩10秒");
    for(int i=0;i<10;i++)
    {
        System.out.println(i+"秒过去了");
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {

            e.printStackTrace();
        }
    }
    System.out.println("去买烟");
    System.out.println("回家");
}
}