non validating dtd ignoring jaxb unmarshalling

/**
* Sample Method to convert the inputstream feed from GSA to JaxB class Gsafeed
*/
public Gsafeed parseRecords(InputStream feedInputStream) {
        SAXParserFactory spf = SAXParserFactory.newInstance();
        spf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
        spf.setFeature("http://xml.org/sax/features/validation", false);
        spf.setNamespaceAware(true); // Binding attributes

        EntityResolver entityResolver = new EntityResolver() {
            @Override
            public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException {
                //To ignore DocType
                if (publicId.equals("-//Google//DTD GSA Feeds//EN")) {
                    return new InputSource(new StringReader(""));
                }

                return null;
            }
        };
        XMLReader xmlReader = spf.newSAXParser().getXMLReader();
        xmlReader.setEntityResolver(entityResolver);
        SAXSource source = new SAXSource(xmlReader, new InputSource(feedInputStream));
        JAXBContext jaxbContext = JAXBContext.newInstance(JAXB-GENERATATED-CLASSES-DIRECTORY);
        Unmarshaller um = jaxbContext.createUnmarshaller();
        gsa = (Gsafeed) um.unmarshal(source);
        return gsa;
}