停止线程

package comm;class StopThread implements Runnable {    private boolean flag = true;    public void run() {        while (flag) {            System.out.println(Thread.currentThread().getName() + "....run");        }    }    public void changeFlag() {        flag = false;    }}public class StopThreadDemo {    public static void main(String[] args) {        StopThread st = new StopThread();        Thread t1 = new Thread(st);        Thread t2 = new Thread(st);        t1.start();        t2.start();        int num = 0;        while (true) {            if (num++ == 10) {                st.changeFlag();                break;            }            System.out.println(Thread.currentThread().getName() + "------"                    + num);        }    }}