Java XML Element create new element with text value

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Text;

public class Main {
   public static void main(String args[]) {
      try {//from   w w w. j  a  va2 s.  c om
         DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
         DocumentBuilder parser = factory.newDocumentBuilder();
         Document doc = parser.parse("data.xml");
         Element root = doc.getDocumentElement();
         TransformerFactory tFactory = TransformerFactory.newInstance();
         Transformer transformer = tFactory.newTransformer();
         DOMSource source = new DOMSource(root);
         StreamResult result = new StreamResult(System.out);
         
         transformer.transform(source, result);
         Text txt = doc.createTextNode("What is DTD?");
         Element e = doc.createElement("question");
         e.appendChild(txt);
         e.setAttribute("id", "q3");
         root.appendChild(e);
         
         transformer.transform(source, result);
      } catch (Exception e) {
         e.printStackTrace();
      }
   }
}