[RESOLVED] Using layouts to place objects?

[Blue1974]

Could really use some help with a homework problem. I need to display a numeric keypad, above the keypad show a label that displays numbers picked, to the right of keypad is another button to clear display. It says to user a border layout to manage overall presentation and grid layout to manage keypad buttons. Put a border around keypad buttons and a border around the display.

I'm not asking anyone to do it because I do want to understand it but I can't get any further at this point, so I could use some help.

I had gotten the grid with the keypad but now I'm not sure how to nest it within a border?

The errors say I'm trying to add the container's parent to itself. I'm trying to put a border around it, I don't understand how this works?

Exception in thread "main" java.lang.IllegalArgumentException: adding container's parent to itself
at java.awt.Container.addImpl(Container.java:1017)
at java.awt.Container.add(Container.java:352)
at KeyPadPanel.<init>(KeyPadPanel.java:42)
at KeyPadDemo.main(KeyPadDemo.java:12)

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

public class KeyPadPanel extends JPanel
{


   public KeyPadPanel()
	{
	   JPanel panel = new JPanel();
		setLayout (new GridLayout (4,3));
		panel.setBorder (BorderFactory.createLineBorder (Color.BLACK, 2)); 


		
		setBackground (Color.green);
		
		JButton b1 = new JButton ("1");
		JButton b2 = new JButton ("2");
		JButton b3 = new JButton ("3");
		JButton b4 = new JButton ("4");
		JButton b5 = new JButton ("5");
		JButton b6 = new JButton ("6");
		JButton b7 = new JButton ("7");
		JButton b8 = new JButton ("8");
		JButton b9 = new JButton ("9");
		JButton b10 = new JButton ("#");
		JButton b11 = new JButton ("0");
		JButton b12 = new JButton ("*");
		
		add (b1);
		add (b2);
		add (b3);
		add (b4);
		add (b5);
		add (b6);
		add (b7);
		add (b8);
		add (b9);
		add (b10);
		add (b11);
		add (b12);
		panel.add(panel);
	}	
}

the driver class

import javax.swing.*;


public class KeyPadDemo extends JPanel
{

   public static void main (String[] args)
	{
      JFrame frame = new JFrame ("KeyPad Demo");
		frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
		
		KeyPadPanel panel = new KeyPadPanel();
		frame.getContentPane().add (panel);
		
		frame.pack();
		frame.setVisible(true);	
	}
	
}