MalformedByteSequenceException Invalid byte 1 of 1-byte UTF-8 sequence

I am coding an xml parser class and when i run it sometimes it works fine but another time it doesnt work and throws this exception ; MalformedByteSequenceException Invalid byte 1 of 1-byte UTF-8 sequence Can anyone help me?Please! Here is my code;

package TRT;



import java.math.BigInteger;
import java.net.URL;
import java.net.URLConnection;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class Gundem {


    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Gundem gundem=new Gundem();
        try {
            URL url=new URL("http://ift.tt/1rOOC8o");
            URLConnection connection=url.openConnection();

            DocumentBuilderFactory builderFactory=DocumentBuilderFactory.newInstance();
            DocumentBuilder docBuilder=builderFactory.newDocumentBuilder();
            Document document=docBuilder.parse(connection.getInputStream());

            Element element=document.getDocumentElement();

            Node node=(Node)element.getChildNodes();
            System.out.println(node.getNodeName());


            NodeList nodeList=node.getChildNodes();
            Node channelNode=(Node)nodeList.item(0);
            System.out.println(channelNode.getNodeName());

            NodeList childNodeListOfChannelNode=channelNode.getChildNodes();

            for(int i=0;i<childNodeListOfChannelNode.getLength();i++){
                Node childNodesOfChannelNode=(Node)childNodeListOfChannelNode.item(i);
                System.out.println(childNodesOfChannelNode.getNodeName());

                if(childNodesOfChannelNode.getNodeName().equals(Constants.ITEM)){
                    Item item=new Item();
                    NodeList itemList=childNodesOfChannelNode.getChildNodes();
                    for(int j=0;j<itemList.getLength();j++){
                        Node childNodeOfItem=itemList.item(j);
                        if(childNodeOfItem.getNodeName().equals(Constants.TITLE)){
                            item.setTitle(childNodeOfItem.getTextContent());
                            System.out.println(item.getTitle());
                            System.out.println(gundem.dumpingInputAsHex(item.getTitle()));
                        }
                        else       if(childNodeOfItem.getNodeName().equals(Constants.DESCRIPTION)){
                            item.setDescription(childNodeOfItem.getTextContent());
                            System.out.println(item.getDescription());
                        }

                    }

                }

            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }



        System.exit(0);  // this line is for solving that problem; JDWP Unable to get JNI 1.2 environment, jvm->GetEnv() return code = -2


        }

    public String dumpingInputAsHex(String input){
        return String.format("%40x",new BigInteger(1,input.getBytes()));
    }

}