各位大虾救命呀

import java.awt.*;
public class YourFrame extends Frame
{
    private Panel borderPanel;
    private Panel flowPanel;
    private Panel gridPanel;
    private Panel cardPanel;
    public YourFrame(String title)
    {
        super(title);
        setSize(600,400);
        setLocation(100,100);
        setBorderLayoutPanel();
        setFlowLayoutPanel();
        setGridLayoutPanel();
        setCardLayoutPanel();
        setLayout(new GridLayout(2,2));
        add(borderPanel);
        add(flowPanel);
        add(gridPanel);
        add(cardPanel);
        addWindListener(new WindowAdapter()
                            {
                                public void windowClosing(WindowEvent e)
                                {
                                    System.exit(0);
                                }
                            });              
    }
    public void setBorderLayoutPanel()
    {
        borderPanel=new Panel();
        borderPanel.setLayout(new BorderLayout());
        Button btn1=new Button("North");
        Button btn2=new Button("South");
        Button btn3=new Button("West");
        Button btn4=new Button("East");
        Button btn5=new Button("Center");
        borderPanel.add(btn1,BorderLayout.NORTH);
        borderPanel.add(btn2,BorderLayout.SOUTH);
        borderPanel.add(btn3,BorderLayout.WEST);
        borderPanel.add(btn4,BorderLayout.EAST);
        borderPanel.add(btn5,BorderLayout.CENTER);
    }
    public void setFlowLayoutPanel()
    {
        flowPanel=new Panel();
        Button btn1=new Button("mybole");
        Button btn2=new Button("winsun");
        flowPanel.add(btn1);
        flowPanel.add(btn2);
    }
    public void setGridLayoutPanel()
    {
        gridPanel=new Panel();
        gridPanel.setLayout(new GridLayout(2,2));
        Button btn1=new Button("Button1");
        Button btn2=new Button("Button2");
        Button btn3=new Button("Button3");
        Button btn4=new Button("Button4");
        gridPanel.add(btn1);
        gridPanel.add(btn2);
        gridPanel.add(btn3);
        gridPanel.add(btn4);
    }
    public void setCardLayoutPanel()
    {
        cardPanel=new Panel();
        cardPanel.setLayout(new CardLayout());
        Button btn1=new Button("黑桃A");
        Button btn2=new Button("红桃K");
        cardPanel.add(btn1,"1");
        cardPanel.add(btn1,"2");
    }
    public static void main(String[] args) throws HeadlessException
    {
        YourFrame fy=new YourFrame("sun");
        fy.show();
    }
}错误提示
"找不到符号          22行"