Java线程的两种实现形式

class Demo extends Thread{
    @Override
    public void run() {
        super.run();
        for(int i=0;i<20;i++)
            System.out.println(Thread.currentThread()+"...."+i);
    }
}

public class ThreadDemo1 {
    public static void main(String[] args){
        Demo d1 = new Demo();
        Demo d2 = new Demo();
        d1.start();
        d2.start();
    }
}

class Demo2 implements Runnable{
    public void run() {
        for(int i=0;i<20;i++)
            System.out.println(Thread.currentThread()+"..."+i);
    }
}

public class ThreadDemo2 {
    public static void main(String[] args) {
        Thread t1 = new Thread(new Demo2());
        Thread t2 = new Thread(new Demo2());
        t1.start();
        t2.start();
        
    }
}