线程插入

public class ThreadJoin {public static void main(String[] args) {Mum m = new Mum();m.start();}}class Mum extends Thread {public void run() {System.out.println("洗菜");System.out.println("切菜");System.out.println("发现没酱油");Son s = new Son();s.start();try {s.join();// //加入。// 一个线程如果执行join语句，那么就有新的线程加入，执行该语句的线程必须要让步给新加入的线程先完成任务，然后才能继续执行。} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}class Son extends Thread {public void run() {System.out.println("儿子下楼");try {Thread.sleep(500);} catch (Exception e) {e.printStackTrace();}System.out.println("儿子一直往前走");System.out.println("儿子打完酱油了");System.out.println("上楼，把酱油给老妈");}}