Problem with JPanels -- probably a simple fix?

Question

Hi all,
I feel really silly, but I cannot for the life of me figure out why my program is acting the way it is. I need to make two windows that are almost identical, except one has an extra panel of 3 buttons on top. For some reason, though, the bottom panel that's supposed to show up on both windows, even though I clearly add it, does not appear, and I can't figure out why. Can anyone give me a quick hand? I posted a SSCCE after my message.
Thanks,
Jezzica85
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Test {
     public static JFrame one, two;
     public static void main(String[] args) {
          JPanel bottomPanel = new JPanel( new GridLayout( 0, 2 ) );
          for( Integer i = 0; i < 2; i++ ) {
               JButton button = new JButton( i.toString() );
          JPanel panel = new JPanel( new GridLayout( 0, 3 ) );
          for( Integer i = 0; i <= 2; i++ ) {
               JButton button = new JButton( i.toString() );
               panel.add( button );
          one = new JFrame( "One" );
          one.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
          one.add( bottomPanel, BorderLayout.SOUTH );
          one.setSize( 770, 580 );
          one.setLocationRelativeTo( null );
          two = new JFrame( "Two" );
          two.add( bottomPanel, BorderLayout.SOUTH );
          two.add( panel, BorderLayout.NORTH );
          two.setSize( 770, 580 );
          two.setLocationRelativeTo( null );
          two.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
          one.setVisible( true );
          two.setVisible( true );
}

Answer 1

You can't add the same component to two containers. Think about it: have you seen a method getParent () in the API? Now if your code worked the way you hoped it would, what wouldbottomPanel.getParent ()return?
Perhaps you could make a private JPanel getBottomPanel () method that returns a new bottomPanel andone.add ( getbottomPanel (), BorderLayout.SOUTH );
two.add ( getbottomPanel (), BorderLayout.SOUTH );db