code: public static void createDebugBorder(JComponent c, Color color) {
          if (color == null) {
              color = Color.BLACK;
          }
          c.setBorder(BorderFactory.createLineBorder(color));
      }
docs: Useful debug function to place a colored, line border around a component
  for layout management debugging.
  
  @param c
  the component
  @param color
  the border color