UnknownHostException in java (that too only sometimes)

Question

Hello,

I am trying to read rss feed of Yahoo but i am unable to make it work properly. The code is absolutely correct , i am sure about it. It works sometimes but sometimes i get UnknownHostException. What can be the reason? Is there some problem with my internet or something else? This is my code :-

 public List<RssFeed> getRssFeed() {

        try {

            List<RssFeed> objList = new ArrayList<RssFeed>();


            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document doc = db.parse("http://rss.news.yahoo.com/rss/india");

            //doc.getDocumentElement().normalize();
            Element docElement = doc.getDocumentElement();
            NodeList objChannelList = docElement.getChildNodes();


            for (int intIndex = 0; intIndex < objChannelList.getLength(); intIndex++) {
                if (objChannelList.item(intIndex).getNodeType() == Node.ELEMENT_NODE) {


                    Element elemItem = (Element) objChannelList.item(intIndex);
                    NodeList itemList = elemItem.getElementsByTagName("item");

                    //show only 3 news
                    int count = itemList.getLength() > 3 ? 3 : objChannelList.getLength();

                    for (int intSubIndex = 0; intSubIndex < count; intSubIndex++) {
                        NodeList itemDetailList = itemList.item(intSubIndex).getChildNodes();
                        String strTitle = ((Node) itemDetailList.item(RSS_VALUES.TITLE.getValue())).getFirstChild().getNodeValue();
                        String strdescription = ((Node) itemDetailList.item(RSS_VALUES.DESCRIPTION.getValue())).getFirstChild().getNodeValue();
                        String strLink = ((Node) itemDetailList.item(RSS_VALUES.LINK.getValue())).getFirstChild().getNodeValue();
                        //System.out.println(strTitle + "\n" + strdescription + "\n" + strLink + "\n\n\n\n");
                        objList.add(new RssFeed(strTitle, strdescription, strLink));
                    }

                }
            }
            return objList;
        } catch (SAXException ex) {
            Logger.getLogger(Utils.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(Utils.class.getName()).log(Level.SEVERE, null, ex);
        } catch (ParserConfigurationException ex) {
            Logger.getLogger(Utils.class.getName()).log(Level.SEVERE, null, ex);
        }

        return null;
    }

Thanks in advance :). This problem has been bugging me since 1 month. Don't know why does Java in this case behave as per its mood :(

Answer 1

An UnknownHostException indicates the host specified couldn't be translated to an IP address. It could very well be a problem with your DNS server.