Thread: JPanel not showing in JFrame

Well I had left GUI's for a while, and now I decided to create one. I got stuck adding my JPanel to my JFrame, and over Google all I found were tons of arguments with revalidate vs validate vs repaint vs awt vs swing. I have already looked at Using Top-Level Containers (The Java™ Tutorials > Creating a GUI With JFC/Swing > Using Swing Components), JPanel (Java 2 Platform SE 5.0) and JFrame (Java Platform SE 6) but that didn't help for this particular problem. I created an SSCCE, here is the code.
JFrame:

import javax.swing.JFrame;
import javax.swing.JComponent;
public class basicJFrame extends JFrame
{
  //Constructors
  /**
   * Create a very simple JFrame, create a new instance of ButtonGrid and show it.
   */
  public basicJFrame()
  {
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    ButtonGrid jpanel = new ButtonGrid();
    getContentPane().add(jpanel);
    ((JComponent)getContentPane()).revalidate(); //Didn't do anything
    setVisible(true);
  }
  //Methods
  public static void main(String[] args)
  {
    new basicJFrame();
  }
}

JPanel:

import java.awt.GridLayout;
 
import javax.swing.JPanel;
import javax.swing.JButton;
/**
 * JButton Grid using JButtons.  Uses GridLayout
 */
public class ButtonGrid extends JPanel 
{
  /**
   * Creates the buttons and adds them
   */
  public void ButtonGrid() 
  {
    setLayout(new GridLayout(3,2));
    add(new JButton("1"));
    add(new JButton("2"));
    add(new JButton("3"));
    add(new JButton("4"));
    add(new JButton("5"));
    add(new JButton("6"));
  }
}

My problem is that the JPanel just will not show up in my JFrame. Thanks for any help

**EDIT**
This should probably be in AWT / Swing forums.. I can't believe I missed that.