code:     private static DocumentBuilder getBuilder() throws ParserConfigurationException {
          ClassLoader loader = Thread.currentThread().getContextClassLoader();
          if (loader == null) {
              loader = DOMUtils.class.getClassLoader();
          }
          if (loader == null) {
              return XMLUtils.getParser();
          }
          DocumentBuilder builder = DOCUMENT_BUILDERS.get(loader);
          if (builder == null) {
              builder = XMLUtils.getParser();
              DOCUMENT_BUILDERS.put(loader, builder);
          }
          return builder;
      }
  
      /**
       * This function is much like getAttribute, but returns null, not "", for a nonexistent attribute.
       * 
       * @param e
       * @param attributeName
       */
  