Substance of Code

I think (and hope) that every developer have been in a situation where a very simple feature just doesn’t work even if everything looks to be okay. This happened to me today when I tried to do a simple thing: I wanted to change the default icon for my JFrame window:

First I tried the obvious solution. I added an image to my package “images\star_16.png” and then tried to use it in constructor like this:

ImageIcon icon;
icon = new ImageIcon("images\star_16.png");
setIconImage( icon.getImage() );

But this didn’t have any effect on the top left icon. It didn’t throw any exceptions or anything. It just didn’t work.

Then I remembered the Toolkit class that I had used in some of the Java Applets so I changed the code to use Toolkit class like this:

Toolkit tk = Toolkit.getDefaultToolkit();
Image icon = tk.getImage("images/star_16.png");
setIconImage(icon);

This didn’t work either. No exceptions or such.

Then I realized that the image I was trying to load was indeed located inside the JAR file so I should probably use some sort of resource handler:

URL iconUrl = URLClassLoader.getSystemResource(
"images/star_16.png");
ImageIcon icon = new ImageIcon( iconUrl );
setIconImage(icon.getImage());

And voilà, it worked!

This entry was posted on Saturday, September 15th, 2007 at 23:49 and is filed under Java. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.