title: JFrame.setIconImage() not working
body: <pre><code>public class RType extends JFrame {
  
  private static ImageIcon ICON = new ImageIcon("craft.png");
  
  public RType() {
  
      add(new Board());
      setIconImage(ICON.getImage());
  
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setSize(400, 300);
      setLocationRelativeTo(null);
      setTitle("R - Type");
      setResizable(false);
      setVisible(true);
  }
  
  public static void main(String[] args) {
      new RType();
  }
  }
  </code></pre>
  
  <p>This code still works fine and compiles after I attempt to set an icon image for the JFrame, but there is no difference. I still see the default java-icon. Can someone detect the problem? "craft.png" is 20x20 pixels. It is correctly placed within the ressource folder (no ClassLoader-exceptions and no other compile-time errors).</p>