JButton question

I have a simple java gui that I wrote which adds 3 buttons and some text. It seems to work, but the buttons seem like they are all different sizes. How to I get them to be all the same size. I tried setSize(), but that did not seem to work. My code is below.

Z.K.


code:

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

public class NotHelloWorld
{
public static void main(String[] args)
{
NotHelloWorldFrame frame = new NotHelloWorldFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}

}

class NotHelloWorldFrame extends JFrame
{
public NotHelloWorldFrame()
{
setTitle("NotHelloWorld");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
NotHelloWorldPanel panel = new NotHelloWorldPanel();
add(panel);


}

public static final int DEFAULT_WIDTH = 300;
public static final int DEFAULT_HEIGHT = 200;
}

class NotHelloWorldPanel extends JPanel
{

public NotHelloWorldPanel()
{
NotHelloWorldButtonPanel bpanel = new NotHelloWorldButtonPanel();
add(bpanel);

}
public void paintComponent(Graphics g)
{
g.drawString("Not a Hello World program", MESSAGE_X, MESSAGE_Y);


}

public static final int MESSAGE_X = 75;
public static final int MESSAGE_Y = 100;

}

class NotHelloWorldButtonPanel extends JPanel
{

public NotHelloWorldButtonPanel()
{
JButton yellowButton = new JButton("Yellow");
JButton blueButton = new JButton("Blue");
JButton redButton = new JButton("Red");

//redButton.setSize(5,10);
//yellowButton.setSize(5,10);
//blueButton.setSize(5,10);

add(yellowButton);
add(blueButton);
add(redButton);



}

}
.