public void save(){
      String fileName = "prueba.xml";
        try
        {
            OutputStream fout= new FileOutputStream(fileName);
            TransformerFactory transFactory = TransformerFactory.newInstance();
            Transformer transformer = transFactory.newTransformer();
            DOMSource source = new DOMSource(this.toXml());
            StreamResult result = new StreamResult(fout);
            transformer.transform(source, result);
        }
        catch( Exception e ){  };
    };