Java Programming

public class FrameDemo2 extends WindowAdapter implements ActionListener {
.....
    protected static Image getFDImage() {
        java.net.URL imgURL = FrameDemo2.class.getResource("/components/images/FD.jpg");
        if (imgURL != null) {
            return new ImageIcon(imgURL).getImage();
        } else {
            return null;
        }
    }
.....
}

I am reading a online tutorial, I would like to ask what does xxx.class.yyy mean? where does the method getResource call from?