//线程的让步////线程class xc1 implements Runnable{    public void run(){        for(int i=1;i<=30;i++){            System.out.println(Thread.currentThread().getName()+"线程___"+i);            if(i%5==0){                System.out.println("=====开始让步======");                //线程的让步                Thread.yield();            }        }    }}public class Index{    public static void main(String[] args){                //线程1        xc1 xc1 = new xc1();        Thread xc1_Thread = new Thread(xc1);        xc1_Thread.start();    //执行线程                //线程2        xc1 xc2 = new xc1();        Thread xc2_Thread = new Thread(xc2);        xc2_Thread.start();    //执行线程            }}