code: public static Document newDocument() throws AlipayApiException {
          Document doc = null;
  
          try {
              doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
          } catch (ParserConfigurationException e) {
              throw new AlipayApiException(e);
          }
  
          return doc;
      }
docs: Creates a new document instance.
  
  @return a new document instance
  @throws ApiException problem creating a new document