throw new DomEx(DomEx.NO_MODIFICATION_ALLOWED_ERR);
throw new DomDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  public Notation declareNotation(String name,                                  String publicId,                                  String systemId)  {    DomNotation notation;        if (isReadonly())      {        throw new DomEx(DomEx.NO_MODIFICATION_ALLOWED_ERR);      }    getNotations();        DomDocument.checkName(name, (owner != null) ?                          "1.1".equals(owner.getXmlVersion()) : false);        notation = new DomNotation(owner, name, publicId, systemId);    notations.setNamedItem(notation);    return notation;  }