@Override
  protected final XmlTag setEmptyXmlTag() {
    throw new UnsupportedOperationException("CollectionElementInvocationHandler.setXmlTag() shouldn't be called;" +
                                            "\nparent=" + getParent() + ";\n" +
                                            "xmlElementName=" + getXmlElementName());
  }
@Override
  protected final XmlTag setEmptyXmlTag()