(yet another) JFrame background image topic

Question

So I know there's about 20 other threads asking this same question, but I've read them all and still can't seem to get my code to work. Here's what I have:
import javax.swing.*;
import java.awt.Image;
import javax.imageio.ImageIO;
public class IndexFrame extends JFrame
    private JButton course1;
    private Image bg = new ImageIcon("background.jpg").getImage();
    public IndexFrame()
     JPanel cp = new JPanel()
         public void paintComponent(java.awt.Graphics g)
          if(bg==null) System.out.println("doh! no pic");
          g.drawImage(bg,0,0,null);
          super.paintComponent(g);
     cp.setOpaque(false);
     setContentPane(cp);
     this.setBounds(100, 100, 1000, 800);
     course1 = new JButton("hi");
     add(course1);
     setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    public static void main(String [] args) {
     IndexFrame frame = new IndexFrame();
     frame.setSize(300,300);
     frame.setVisible(true);
}Needless to say, it doesn't work, and I have no idea why. It appears to be loading the pic correctly, because bg is not null (doesn't print the error message). Any help figuring out what's going on would be greatly appreciated!
On the bright side, I've learned a lot about Swing in trying to fix my problem; here's a question though. Is it ever a good idea to override a Swing object's (e.g. a JFrame) paint method? Or, unlike AWT, should you only override the paintcomponent()? And if so, why?
Thanks!

Answer 1

I've had problems with ImageIcon reading. For one
thing, if it can't find the file, it won't always
tell you. I had to give the absolute path a number of
times for it to be able to find the actual image
file.Hrm, so I guess I assumed it had loaded the file since bg was no longer null. It turns out you were right. I replaced the line:
private Image bg = new ImageIcon("background.jpg").getImage();with:
ImageIcon blah = new javax.swing.ImageIcon(getClass().getResource("background.jpg"));
bg = blah.getImage();in the IndexFrame constructor, and now it magically works! Just for future reference for me, any idea why the first way I did it didn't work? Was I using ImageIcon incorrectly? Also, is there a better way of handling images? I've come across the ImageIO class, but wasn't sure what that was intended for.
Thanks again!