java语言中用Eclipse话圆，为什么图形不显示出来？

package edu.pku.tds;

import java.awt.*;
import javax.swing.*;

public class ph7423 extends JFrame {

private static final long serialVersionUID = 1L;
public static void main(String[] argv){
JFrame frame=new ph7423();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(600,600);
frame.setVisible(true);
}
public void pain(Graphics g){
g.drawString("circle 99", 20, 20);
int x0=getSize().width/2;
int y0=getSize().height/2;

for(int r=0;r<getSize().height/2;r+=10){
g.drawOval(x0-r, y0-r, r*2, r*2);
}
}
Color getRandomColor(){
return new Color(
(int) (Math.random()*256),
(int) (Math.random()*256),
(int) (Math.random()*256)
);

}
}
请大侠明示哪里有问题？小弟谢过了！！！

public void paint(Graphics g){ /////////////这打错单词了

super.paint();/////////////////////添加一行
g.drawString("circle 99", 20, 20);