Loading resources like images while running project distributed as JAR archive

awt, embedded-resource, java, nullpointerexception, swing

Solution

First of all, change this line :

image = ImageIO.read(getClass().getClassLoader().getResource("resources/icon.gif"));

to this :

image = ImageIO.read(getClass().getResource("/resources/icon.gif"));

More info, on as to where lies the difference between the two approaches, can be found on this thread - Different ways of loading a Resource

For Eclipse:

- How to add Images to your Resource Folder in the Project

For NetBeans:

- Handling Images in a Java GUI Application

- How to add Images to the Project

For IntelliJ IDEA:

- Right-Click the src Folder of the Project. Select New -> Package

- Under New Package Dialog, type name of the package, say resources. Click OK

- Right Click resources package. Select New -> Package

- Under New Package Dialog, type name of the package, say images. Click OK

- Now select the image that you want to add to the project, copy it. Right click resources.images package, inside the IDE, and select Paste

Use the last link to check how to access this file now in Java code. Though for this example, one would be using

`getClass().getResource("/resources/images/myImage.imageExtension");`

Press Shift + F10, to make and run the project. The resources and images folders, will be created automatically inside the out folder.

If you are doing it manually :

- How to add Images to your Project

- How to Use Icons

- A Little extra clarification, as given in this answer's first code example.

QUICK REFERENCE CODE EXAMPLE(though for more detail consider, A little extra clarification link):

package swingtest;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;

/**
 * Created with IntelliJ IDEA.
 * User: Gagandeep Bali
 * Date: 7/1/14
 * Time: 9:44 AM
 * To change this template use File | Settings | File Templates.
 */
public class ImageExample {

    private MyPanel contentPane;

    private void displayGUI() {
        JFrame frame = new JFrame("Image Example");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        contentPane = new MyPanel();

        frame.setContentPane(contentPane);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private class MyPanel extends JPanel {

        private BufferedImage image;

        public MyPanel() {
            try {
                image = ImageIO.read(MyPanel.class.getResource("/resources/images/planetbackground.jpg"));
            } catch (IOException ioe) {
                ioe.printStackTrace();
            }
        }

        @Override
        public Dimension getPreferredSize() {
            return image == null ? new Dimension(400, 300): new Dimension(image.getWidth(), image.getHeight());
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.drawImage(image, 0, 0, this);
        }
    }

    public static void main(String[] args) {
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                new ImageExample().displayGUI();
            }
        };
        EventQueue.invokeLater(runnable);
    }
}

Problem

Original source

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