Help with creating a new XML file from an existing DOM tree!!

Question

i want to create a new XML file from an existing DOM tree
i used this code to create a new document:
static public Document createDocument(String fileName) throws ParserConfigurationException//,IOException,SAXException
          try {
               DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
               factory.setIgnoringComments(true);
               factory.setIgnoringElementContentWhitespace(true);
               factory.setValidating(true);
               DocumentBuilder builder =factory.newDocumentBuilder();
               return builder.newDocument();
//          handle exception creating DocumentBuilder
          catch ( ParserConfigurationException parserError ) {
                    throw new ParserConfigurationException();
          }then i used this code to transform the DOM :
public void exportDocument(Document document) {
          try {
               Source xmlSource = new DOMSource( document );
               Result result = new StreamResult( System.out );
               TransformerFactory transformerFactory =
                    TransformerFactory.newInstance();
               Transformer transformer =transformerFactory.newTransformer();
               transformer.setOutputProperty( "indent", "yes" );
               transformer.transform( xmlSource, result );
       //then catching the exceptions
But the file was not created and i didn't find where can i specify the DTD that the XML file should use and where can i enter the name of the XML file itself
Another questoin can i write a DTD file dynamically during the execution of the program??

Answer 1

Cross-post: http://forum.java.sun.com/thread.jspa?threadID=784467&messageID=4459240#4459240