public class Thread1 extends Thread{    public void run(){        int i=0;        while(i<10){            i++;            System.out.println(i);        }    }        public static void main(String[] args){        Thread1 t=new Thread1();        t.start();    }}

public class Thread2 implements Runnable{    @Override    public void run() {        int i=10;        while(i>0){            i--;            System.out.println(i);        }    }        public static void main(String[] args){        Thread2 t=new Thread2();        new Thread(t).start();    }}

线程，较难讲透，初学者不易掌握，带过即可。