throw new Error("Do not use add() on JInternalPane directly. Use getContentPane().add() instead");  super.addImpl(comp, constraints, index);
throw new Error("Do not use add() on JInternalFrame directly. Use " + "getContentPane().add() instead"); getContentPane().add(comp, constraints, index); }
  protected void addImpl(Component comp, Object constraints, int index)  {    if (isRootPaneCheckingEnabled())      throw new Error("Do not use add() on JInternalPane directly. Use getContentPane().add() instead");    super.addImpl(comp, constraints, index);  }