JavaÐÂÊÖ ¸ßÊÖ¿´¿´ - Java / Java SE

package Demo1;
/**
 * 
 * @author Administrator
 *
 */
import java.awt.*;

import javax.swing.*;
import java.awt.event.*;
  public class Test3 extends JFrame implements ActionListener
{
  public static void main(String[] args)
  {
Test3 t=new Test3();
  }
  MyPanel1 mp=new MyPanel1();
  JButton jb1=null;
  JButton jb2=null;
  public Test3()
  {
mp=new MyPanel1();
Cat cat=new Cat();
mp.setBackground(Color.black);
jb1=new JButton("ºÚÉ«");
jb2=new JButton("ºìÉ«");
 
this.add(jb1,BorderLayout.NORTH);
this.add(mp);
this.add(jb2,BorderLayout.SOUTH);
 
jb1.addActionListener(this);
jb1.setActionCommand("a");
jb1.addActionListener(cat);
 
jb2.addActionListener(this);
jb2.addActionListener(cat);
jb2.setActionCommand("b");
 
this.setSize(300,200);
this.setVisible(true);
this.setDefaultCloseOperation
(JFrame.EXIT_ON_CLOSE);
}

public void actionPerformed(ActionEvent e) {
if(e.getActionCommand().equals("a"))
{
System.out.println("ÄãµãÁ˺ÚË¿°´Å¥");
mp.setBackground(Color.black