Add images to jar

Question

I want to set icon to my JFrame. I do the following:

Image icon = Toolkit.getDefaultToolkit().getImage("src/images/icon.jpg");
this.setIconImage(icon);

It works fine when I run this code from netbeans, but when I try to run this code from jar file, images are not shown in my JFrame. I have tried to load images as resources:

this.setIconImage(Toolkit.getDefaultToolkit().getImage(getClass().getResource("/src/images/icon.jpg")));

but when I run this code it fails with NullPointerException

 Uncaught error fetching image:
java.lang.NullPointerException
        at sun.awt.image.URLImageSource.getConnection(URLImageSource.java:99)
        at sun.awt.image.URLImageSource.getDecoder(URLImageSource.java:113)
        at sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.java:240)
        at sun.awt.image.ImageFetcher.fetchloop(ImageFetcher.java:172)
        at sun.awt.image.ImageFetcher.run(ImageFetcher.java:136)

How can I do this work?

edit: Thanks to all, the problem was solved by specifying image as

Toolkit.getDefaultToolkit().getImage(getClass().getClassLoader().getResource("images/icon.JPG"))

As for it seems rather weird, and would be better if it was like

this.setIconImage(new ImageIcon(pathToIcon).getImage());

Answer 1

Assuming your JAR file has a top level directory called images, you can use either:

1. getClass().getResource("/images/icon.jpg") or
2. getClass().getClassLoader().getResource("images/icon.jpg")

Answer 2

Looking at the source code of URLImageSource, it appears that the reason that getConnection throws an NPE is that it has a null for the url. And that leads me to suspect that

getClass().getResource("/src/images/icon.jpg")

is returning null. It would do that if it could not locate a resource with that pathname.

I bet that the problem is that you've got the path wrong.

To prove / disprove this, you should run jar tvf on the JAR file, and look for the line that matches "icon.jpg". Is the corresponding pathname the same as what you are using? If not, use the pathname from the matching line in the getResource call and it should work. Alternatively, if the file doesn't show up at all, look at the NetBeans build configs that tell it what to put in the JAR file. (I'm not a NetBeans user, so I can't say where you would need to look ...)

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If that leads you absolutely nowhere, another possibility is that getClass().getResource(...) is using a classloader that doesn't know about the JAR file containing the image. (This seems pretty improbable to me ...)