实现一个Runnable。在run()内部打印一个消息，然后调用yield()。重复这个操作3次，然后从run()中返回。在构造器中放置一条启动消息，并且放置一条在任务终止时的关闭消息，然后使用线程创建大量的这种任务。
package com.test;
public class Test1 implements Runnable {
private String start;
private String end;
@Override
public void run() {
System.out.println(this+start+" start");;
for (int i=0;i<3;i++) {
System.out.println("running "+i);
Thread.yield();
}
System.out.println(this+end+" end");
}
public Test1(String start,String end) {
this.start = start;
this.end = end;
}
public static void main(String[] args) {
Test1 test = new Test1("开始", "结束");
Thread t1 = new Thread(test);
Thread t2 = new Thread(test);
Thread t3 = new Thread(test);
t1.start();
t2.start();
t3.start();
}
}
