Class.getResource() returns null

Question

I am trying to display pictures on the JPanel but I keep getting the error : java.lang.IllegalArgumentException: input == null! I don't understand what is happening. Here is the code I am using: ``` public void actionPerformed(ActionEvent e) { try { Image image=ImageIO.read(getClass().getResource("img/" +num.getText()+".jpg")); Image resized = image.getScaledInstance(200, 200, 100); pictureFrame.setIcon(new ImageIcon(resized)); } catch (Exception ex){ ex.printStackTrace(); } } ``` This just leads to me getting the error! Stack trace produces the following: ``` Java.lang.IllegalArgumentException: input == null! at javax.imageio.ImageIO.read(ImageIO.java:1362) at work.Item.actionPerformed(Item.java:96) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387) at javax.swing.DefaultButtonModel.setPressed(Defau…

Accepted Answer

Assuming `getClass()` returns `com.foo.bar.MyActionListener`, `getClass().getResource("img/foo.jpg")` looks for a file named `foo.jpg` in the package `com.foo.bar.img`. If the image is not in this package, or if it is in this package but its root directory is not in the classpath, the method will return null.

If the img folder is at the root of the classpath, you should use `getClass().getResource("/img/foo.jpg")` (note the leading `/`), or `getClass().getClassLoader().getResource("img/foo.jpg")`.

Class.getResource() returns null

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