image not showing up after button click

im having trouble in adding an image after a button is clicked, ive only added the code with the jlabel/imageicon

JLabel picture;     
public Check() {   
    picture = new JLabel(createImageIcon("images\\exit.png"));   
    add(picture, BorderLayout.WEST);   
}   

 public void actionPerformed(ActionEvent e) {   
    picture.setIcon(createImageIcon("images\\update.png"));   
    }   

protected static ImageIcon createImageIcon(String path) {   
    java.net.URL imgURL = Check.class.getResource(path);   
    System.err.println(imgURL);   
    if (imgURL != null) {   
        return new ImageIcon(imgURL);   
    } else {   
        System.err.println("Couldn't find file: " + path);   
        return null;   

    }   
}

i always get null for the path, what could be the problem

the image path is correct as when i tested another way,

public Check() {   
String imgStr = "images\\exit.png";   
     ImageIcon image = new ImageIcon(imgStr);   
     JLabel label1 = new JLabel(image, JLabel.CENTER);   
     JPanel South = new JPanel();   
     South.add(label1);   
     add("South", South);   
}

the image appears, but this is done when i run it, the image is there already and not when i click a button.

thanks

Solution

Please try picture.setIcon(createImageIcon("/images/update.png")); since it looks like that you image is loaded from classpath.

See here:

Finds a resource with a given name. This method returns null if no resource with this name is found. The rules for searching resources associated with a given class are implemented by the * defining class loader of the class.

This method delegates the call to its class loader, after making these changes to the resource name: if the resource name starts with "/", it is unchanged; otherwise, the package name is prepended to the resource name after converting "." to "/". If this object was loaded by the bootstrap loader, the call is delegated to ClassLoader.getSystemResource.

http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/Class.html#getResource%28java.lang.String%29