没看出错在哪里，请老司机帮看看，谢谢

执行不了，但没看出来哪里有错，请老司机帮看看。

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

    public class Gaibianyanse extends JFrame implements ActionListener{
     Button bt1,bt2;
     JPanel jp1,jp2;
   
    public static void main(String[] args) {
        Gaibianyanse keke=new Gaibianyanse();
    }

    public Gaibianyanse() {
        bt1=new Button("红色");
        bt2=new Button("绿色");
        jp1=new JPanel();
        jp2=new JPanel();
        bt1.addActionListener(this);
        bt2.addActionListener(this);
        bt1.setActionCommand("Tutu");
        bt2.setActionCommand("Kaka");
        jp2.add(bt1);
        jp2.add(bt2);
        jp2.setLayout(new FlowLayout(FlowLayout.CENTER));
        
        this.setLayout(new GridLayout(2,1));
        this.add(jp1);
        this.add(jp2);
        
        this.setTitle("改颜色的面板");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
        this.setLocation(300, 300);
        this.setSize(300,300);        
    }
   
    public void ActionPerformed(ActionEvent e) {
        if(e.getActionCommand().equals("Tutu")) {
            jp1.setBackground(Color.BLACK);
        }
        else if(e.getActionCommand().equals("Kaka")) {
            jp1.setBackground(Color.RED);
            }
    }
    }