Null Pointer Exception Adding a Toolbar

Question

I am trying to add a toolbar to my program but when I add the code, I am getting a nullpointerexception, anyone know why this may be happening?

public JButton makeButton(String imageName,
        String toolTipText) {
//Look for the image.
String imgLocation = "images/" + imageName + ".jpg";
URL imageURL = assignment3.class.getResource(imgLocation);

//Create and initialize the button.
JButton button = new JButton();
button.setToolTipText(toolTipText);
button.addActionListener(this);

button.setIcon(new ImageIcon(imageURL));

return button;
}

The exception is

Exception in thread "main" java.lang.NullPointerException 
at javax.swing.ImageIcon.<init>(Unknown Source) 
at assignment3.assignment3.makeButton(assignment3.java:331) 

Answer 1

"I am getting a nullpointerexception, anyone know why this may be happening?"

java.lang.NullPointerException at javax.swing.ImageIcon

You're getting a nullpointerexception because the URL is null, due to a bad path, and you're passing a null URL to the ImageIcon

You need another / in front of the path

String imgLocation = "/images/" + imageName + ".jpg";
                      ^

And you images needs to be directly a child of the src

ProjectRoot
          src
              images
                   someimage.jpg