import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class testCard
{
    public static void main(String [] args)
    {
        demo_8 test=new demo_8();
    }
}

 class demo_8 extends JFrame  
 {
     JPanel jp;//最底部的面板
     JPanel jpNorth;//放置card的面板
     JPanel jpButton;//放置按钮的面板
     JPanel jp1;
     JPanel jp2;
     JPanel jp3;
     JPanel jp4;
     JPanel jp5;
     JButton jb1;
     JButton jb2;
     CardLayout card=new CardLayout();
     public demo_8()
     {
         jp=new JPanel();
         jpButton=new JPanel();
         this.setBounds(0,0,400,300);
         this.setVisible(true);
         this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         this.setContentPane(jp);
         jpNorth=new JPanel();
         jp.add(jpNorth,BorderLayout.CENTER);
         jpNorth.setLayout(card);
         jp1=new JPanel();
         jp2=new JPanel();
         jp3=new JPanel();
         jp4=new JPanel();
         jp5=new JPanel();
         jb1=new JButton("jb1");
         jb2=new JButton("jb2");
         jp.add(jpButton,BorderLayout.SOUTH);
         jpButton.add(jb1);
         jpButton.add(jb2);
         card.addLayoutComponent(jp1,"jp1");
         card.addLayoutComponent(jp2,"jp2");
         card.addLayoutComponent(jp3,"jp3");
         card.addLayoutComponent(jp4,"jp4");
         jb1.addActionListener
         (
             new ActionListener()
             {
                 public void actionPerformed(ActionEvent e)
                 {
                     card.previous(jp2);
                 }
             }
         );
         jb2.addActionListener(
             new ActionListener()
             {
                 public void actionPerformed(ActionEvent e)
                 {
                     card.next(jp1);
                 }
                 
             }
         );
     }
 }


报错图：

这个程序是我自己写的我用ediplus编写的 ？？
我也找不出原因，在网上也没找到答案，所以在此请教各位大神，还望楼上的不吝赐教，呵呵呵额 谢谢

哦 找到了  谢谢 是我的放置方法弄错了 ，谢谢提醒