docs: static public String getRootNodeName(String xml)
      {
          String rootNodeName = null;
          try {
              DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
              dbf.setExpandEntityReferences(false);
              DocumentBuilder dBuilder = dbf.newDocumentBuilder();
              InputSource inputSource = new InputSource(new StringReader(xml));
              Document doc = dBuilder.parse(inputSource);
              doc.getDocumentElement().normalize();
              rootNodeName = doc.getDocumentElement().getNodeName();
          } catch (SAXException e) {
              System.out.println("SAX exception: " + e);
          } catch (IOException e) {
              System.out.println("IO exception: " + e);
          } catch (ParserConfigurationException e) {
              System.out.println("ParserConfiguration exception: " + e);
          }
          return rootNodeName;
      }