Image Icon with JAR

Question

Hi,
I would like to replace the standard coffee cup window icon with a custom image for a stand-alone Swing application, all packaged as a JAR file. As a quick test, I wrote the following:
package me.swinginfo1;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
public class IconWindow extends JFrame {
     public IconWindow() {
          this.setSize(300, 200); //set the window size
          this.setLocationRelativeTo(null); //centers window on screen
          this.setTitle("Window with Icon"); //set the window title
          this.setDefaultCloseOperation(EXIT_ON_CLOSE); //end the program when window closed
          java.net.URL imageURL = this.getClass().getResource("images/red_circle.png");
          this.setIconImage(new ImageIcon(imageURL).getImage());
     * Executes Swing window... no arguments.
     public static void main(String[] args) {
          IconWindow myWindow = new IconWindow();
          myWindow.setVisible(true);
When I run this class from the IDE (Eclipse, in this case), the program runs fine, and my icon image appears in the corner of the window as desired. However, when I package the program into a JAR, the JAR will not execute. My method of packaging is simply to use File -> Export -> JAR.
Note: if I comment out the two lines related to the Icon Image, then the JAR executes as expected (but without my custom image icon, of course).
I am concerned that perhaps the resource folder containing the image is not being included in the JAR. Is there an easy way to check this? Or is there something else I am doing wrong?
Thanks!

Answer 1

Thanks for the information atmguy. After checking the jar contents, I found that my resource files (the "red_circle.png" in this case) were not being packaged into the jar. It looks like the reason for this was that I had just added the directory to my project "src" directory by hand, rather than importing the files with Eclipse. Thus, when I packaged the jar using Eclipse, it was unaware of the resource files and therefore did not include them in the jar.
Also, I found that in Windows a handy way of quickly viewing jar files is to rename the jar as a .zip, and then just explore the zip file. (As mentioned here: http://en.kioskea.net/faq/sujet-556-to-see-the-content-of-a-jar-file).
The jar now executes as expected. Thanks!