if (!initStageDone)
if (isRootPaneCheckingEnabled()) getContentPane().add(comp, constraints, index); else
  protected void addImpl(Component comp, Object constraints, int index)  {    // If we're in the initialization stage use super.add. Here we add the    // rootPane as well as the title bar and other stuff.    // Otherwise pass the add onto the content pane.    if (!initStageDone)      super.addImpl(comp,constraints, index);    else      {    if (isRootPaneCheckingEnabled())          throw new Error("Do not use add() on JInternalFrame directly. Use "                           + "getContentPane().add() instead");        getContentPane().add(comp, constraints, index);      }  }