XML : JAXB return 403 error after parsing stackoverflow RSS

  JAXBContext jc = JAXBContext.newInstance(StackOverflowXPathMap.class);        Unmarshaller unmarshaller = jc.createUnmarshaller();        URL xmlURL = new URL("http://stackoverflow.com/feeds");        URLConnection conn = xmlURL.openConnection();      conn.addRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.86 Safari/537.36");      conn.connect();        InputStream xml = xmlURL.openStream();      StackOverflowXPathMap stackOverflowXPathMap = (StackOverflowXPathMap) unmarshaller.unmarshal(xml);      System.out.println(stackOverflowXPathMap.getAuthor());      xml.close();        Marshaller marshaller = jc.createMarshaller();      marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);      marshaller.marshal(stackOverflowXPathMap, System.out);    

I`m trying to parse RSS from stackowerflow, but I have some troubles. Exception in thread "main" java.io.IOException: Server returned HTTP response code: 403 for URL: http://stackoverflow.com/feeds