Android : InputStream throws exception for the below code

My InputStream throws exception for the below code I'm not able to find what error I have made tried from morning to debug and got feed up with it

Please help.

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        public class MainActivity extends Activity {

        Element RootElement;
        Element xmlElement;
        Context context;
        TextView textView1;
        String url = "http://www.androidbegin.com", s;
        ProgressDialog mProgressDialog;
        String UrlLink = "http://postimg.org/gallery/5y7ulm9o/b2f8235e/";

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            textView1 = (TextView) findViewById(R.id.textView1);
            context = this;

            Gethtml Ght = new Gethtml();
            Ght.execute();
        }

        public class Gethtml extends AsyncTask {
            ProgressDialog dialog;

            @Override
            protected void onPreExecute() {
                // TODO Auto-generated method stub
                super.onPreExecute();
                dialog = new ProgressDialog(context);
                dialog.setTitle("Loading");
                dialog.setMessage("Html....");
                dialog.show();
            }

            @Override
            protected Object doInBackground(Object... params) {
                try {
                HttpClient client = new DefaultHttpClient();
                HttpGet request = new HttpGet(UrlLink);
                HttpResponse response = client.execute(request);
                StatusLine line = response.getStatusLine();
                int statuscode = line.getStatusCode();
                if (statuscode != 200) {
                    return null;
                }
 /*throws error---->*/ InputStream IpStream=response.getEntity().getContent();
                processXML(IpStream);
                }
                catch(Exception e){
                    Log.v("Error",e.toString());
                }

                return null;
            }
    public void processXML(InputStream IS)throws Exception{
        DocumentBuilderFactory DBF=DocumentBuilderFactory.newInstance();
        DocumentBuilder DB=DBF.newDocumentBuilder();
        org.w3c.dom.Document xmlDocument=DB.parse(IS);
        Element RootElement=xmlDocument.getDocumentElement();

    }
            @Override
            protected void onPostExecute(Object result) {
                dialog.dismiss();
                Log.v("VIVZ",RootElement.getTagName());
             Toast.makeText(MainActivity.this, "text", Toast.LENGTH_SHORT).show();
                textView1.setText(s);
                 //super.onPostExecute(result);
            }

        }

    }

Logcat