Question

Problem is the following – I am writing a program with Eclipse in java..
The resulting folder structure is main project folder: Animal Classification/ inside of it: bin/ , images/, pics/ in the bin/ folder : users/metropolia/allClasses.class

Program starts normally and works -> images are in the folders images/ and pics/ -> they are used by users.metropolia.Hieararchy

But when I create a .jar out of it either through Eclipse or through CMD.exe -> in the folder different from the source folder the jar does not show images even though they are packed inside of it. Inside the Hierarchy.class the path to the images is (“images/name.jpg” or “pics/name.jpg”).

Then I tried to use the ClassLoader.getSystemResource(“images/name.jpg”) – but now the eclipse and the cmd.exe give warnings and dont start the program -> NullPointerException in thread main = mistake in the line where ClassLoader static is used…

I would really appreciate any help

Update:

http://users.metropolia.fi/~artemm/

Download the code from there plz
It can be downloaded as SFX-archive or if you are afraid of viruses just download usual RAR archive

I really appreciate your help

Main class is in users/metropolia/Program.java

Update 2:

@MockerTim

THank you very much for your help – now everything works. Moreover, I managed to find one more snag – it didnt call for the images, because the call was : “Fish.jpg” and the picture was : “fish.jpg” – no wonder it could not find anything and gave mistakes.

THank you very much once again, I really appreciate!

Answer 1

You are using incorrect paths.

You should use the following paths in your code:
../../images/name.jpg and ../../pics/name.jgp, respectively.

As Nate mentioned, you can start you path with “/”, and use /images/name.jpg and /pics/name.jpg, respectively.

When you use images/name.jpg path in the class users.metropolia.Hieararchy, your code tries to find file name.jpg in the folder users/metropolia/images. And, of course, it fails.

See Locating resources in Java for details.

Here is the simple example:

package users.metropolia;

import java.net.URL;
import javax.swing.ImageIcon;

public class IconManager {
    /** Returns an ImageIcon, or null if the path was invalid. */
    public static ImageIcon loadImageIcon(String path) {
        URL imgURL = IconManager.class.getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find file: " + path);
                return null;
        }
    }

    public static void main(String[] args) {
        // Using absolute (to jar) paths
        ImageIcon icon3 = loadImageIcon("/pics/spider.jpg");
        ImageIcon icon4 = loadImageIcon("/imagess/ant.jpg");
    }
}

Update:

I’ve downloaded your code (from your link), and added the above IconManager class and used its loadImageIcon() method to initialize your anImages array and MyDrawPanel class.
Now your progam looks like this:

The changes, that I’ve made to your code:

In class Hierarchy:

for (int i = 0; i < options.length; i++) {
  //anImages[i] = new ImageIcon("/images/" + options[i] + ".jpg");
    anImages[i] = IconManager.loadImageIcon("/images/" + options[i] + ".jpg");
    listObj[i] = new RendObject(options[i], anImages[i]);
}

In class MyDrawPanel:

public MyDrawPanel(String x) {
  //picture = new ImageIcon(x).getImage();
    picture = IconManager.loadImageIcon(x).getImage();
}

And, of course, I removed “generic” from JComboBox where needed.

Remark: To make your program show selected image instead of spider image, you should modify your program further.