code: private Catalogo copy(Catalogo catalogo) throws Exception {
  	    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
  	    dbf.setNamespaceAware(true);
  	    DocumentBuilder db = dbf.newDocumentBuilder(); 
  	    Document doc = db.newDocument();
  	    Marshaller m = context.createMarshaller();
  	    m.marshal(catalogo, doc);
  	    Unmarshaller u = context.createUnmarshaller();
  	    return (Catalogo) u.unmarshal(doc);
  	  }
docs: Defensive deep-copy