I am having a error for my GUI. Trying to set title bar icon then be included in a Runnable JAR.

BufferedImage image = null;
try {
    image = ImageIO.read(getClass().getClassLoader().getResource("resources/icon.gif"));
catch (IOException e) {


Here is the error I am getting:

Exception in thread "main" java.lang.IllegalArgumentException: input == null!
    at javax.imageio.ImageIO.read(Unknown Source)
    at GUI.<init>(GUI.java:39)
    at GUI.main(GUI.java:351)

The image is in the correct directory which "resources" folder is the root of the project file

Solution 1

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:

For NetBeans:

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


  • 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 :

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");

        contentPane = new MyPanel();


    private class MyPanel extends JPanel {

        private BufferedImage image;

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

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

        protected void paintComponent(Graphics g) {
            g.drawImage(image, 0, 0, this);

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

Solution 2

There's a much easier way to load and set an image as a frame icon:

    new ImageIcon(getClass().getResource("/resources/icon.gif")).getImage());

And thats all :)! You don't even have to use a try-catch block because ImageIcon does not throw any declared exceptions. And due to getClass().getResource(), it works both from file system and from a jar depending how you run your application.

If you need to check whether the image is available, you can check if the URL returned by getResource() is null:

URL url = getClass().getResource("/resources/icon.gif");
if (url == null)
    System.out.println( "Could not find image!" );
    frame.setIconImage(new ImageIcon(url).getImage());

Solution 3

The image files must be in the directory resources/ in your JAR, as shown in How to Use Icons and this example for the directory named images/.