Java多线程的第二种方式--接口

class Thread {
private Runnable r;
Thread(){

}
Thread(Runnable r){
this.r=r;
}
public void run(){
if(r!=null)
r.run();
}
public void start() {
run();
}
}

class ThreadImpl implements Runnable{
public void run(){
System.out.println("runnable run");
}
}

public class Test {

public static void main(String[] args) {
ThreadImpl i=new ThreadImpl();
Thread t=new Thread(i);
t.start();
}

}