code: public XMLNode parseXML(String root) throws DocFileIOException, SimpleDocletException {
          if (!xmlElementsMap.containsKey(root)) {
              try {
                  currentRoot = root;
                  isParsing = false;
                  SAXParserFactory factory = SAXParserFactory.newInstance();
                  SAXParser saxParser = factory.newSAXParser();
                  InputStream in = configuration.getBuilderXML();
                  saxParser.parse(in, this);
              } catch (IOException | ParserConfigurationException | SAXException e) {
                  String message = (configuration.builderXMLPath == null)
                          ? configuration.getResources().getText("doclet.exception.read.resource",
                                  Configuration.DEFAULT_BUILDER_XML, e)
                          : configuration.getResources().getText("doclet.exception.read.file",
                                  configuration.builderXMLPath, e);
                  throw new SimpleDocletException(message, e);
              }
          }
          return xmlElementsMap.get(root);
      }
docs: Parse the XML specifying the layout of the documentation.
  
  @param root the name of the desired node
  @return the list of XML elements parsed.
  @throws DocFileIOException if there is a problem reading a user-supplied build file
  @throws SimpleDocletException if there is a problem reading the system build file