public static Persistence getPersistence(URL url) throws Exception 
{
        InputStream persistenceDescriptor = null;
        try {
            persistenceDescriptor = url.openStream();
            JAXBContext jc = JAXBContextFactory.newInstance(Persistence.class);
            Unmarshaller u = jc.createUnmarshaller();
            UnmarshallerHandler uh = u.getUnmarshallerHandler();
            // create a new XML parser
            SAXParserFactory factory = SAXParserFactory.newInstance();
            factory.setNamespaceAware(true);
            factory.setValidating(true);
            SAXParser parser = factory.newSAXParser();
            XMLReader xmlReader = parser.getXMLReader();
            // Create a filter to intercept events
            PersistenceFilter xmlFilter = new PersistenceFilter(xmlReader);
            // Be sure the filter has the JAXB content handler set (or it wont
            // work)
            xmlFilter.setContentHandler(uh);
            SAXSource source = new SAXSource(xmlFilter, new InputSource(persistenceDescriptor));
            return (Persistence) u.unmarshal(source);
        } finally {
            if (persistenceDescriptor != null) persistenceDescriptor.close();
        }
}