code:     private static DocumentBuilderFactory createDocumentBuilderFactory() throws ParserConfigurationException {
          DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
          dbf.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING , true);
  
          dbf.setValidating(false);
          dbf.setIgnoringComments(false);
          dbf.setIgnoringElementContentWhitespace(true);
          dbf.setNamespaceAware(true);
          // dbf.setCoalescing(true);
          // dbf.setExpandEntityReferences(true);
          
          return dbf;
      }
  
      /**
       * Read XML as DOM.
       */
  