import java.awt.*;

public class FlyingBoll {

public static void main(String arg[]){

Frame fm = new Frame();

fm.setSize(1368, 768);

fm.setBackground(Color.blue);

MyPanel css = new MyPanel();

fm.add(css);

Thread t = new Thread(css); //建立线程

t.start(); //此时的线程处于就绪状态，随时等待CPU的轮转调度

fm.show();

System.out.println("Hello~");

}

}

class MyPanel extends Panel implements Runnable{

int x = 300;

int y = 100;

public void paint(Graphics G){

G.setColor(Color.WHITE);

G.fillOval(x, y, 50, 50);

/* int x=300,y=100;

while(y<700){

G.setColor(Color.WHITE);

G.fillOval(x, y, 50, 50);

//G.setColor(Color.blue);

G.fillOval(x, y, 50, 50);

//x=x+3;

y=y+3;

}*/

}

public void run(){

while(true){

y++;x++;

if(y>600 || x>1000){

y = 10;

x = 10;

}

try{

Thread.sleep(10);

}catch(Exception e){}

repaint(); //发出repaint的系统调用，系统见到后会调用paint，进行重画操作；

}

}

}