title: How to resolve java.net.UnknownHostException
body: <p>I was taken internet permission in manifest file. My mobile network connection is also working.
  The main code:</p>
  
  <pre><code>/**
   * Created by Yogesh on 5/07/2016.
   */
  public class All_Item_Fragment extends android.support.v4.app.ListFragment {
      // Declare Variables
      JSONArray jsonarray = null;
      ListView list;
      ListViewAdapter adapter;
      ArrayList&lt;HashMap&lt;String, String&gt;&gt; itemlist;
      static String NAME = "name";
      static String DESCRIPTION = "Description";
      static String PRICE = "price";
      static String IMAGE = "image_path";
  
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
          View view = inflater.inflate(R.layout.all_item_layout, container, false);
          itemlist = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;();
          new ReadJSON().execute();
          list = (ListView) view.findViewById(android.R.id.list);
  
          return view;
      }
  
      private class ReadJSON extends AsyncTask&lt;Void, Void, Void&gt; {
          @Override
          protected void onPreExecute() {
              super.onPreExecute();
          }
  
          @Override
          protected Void doInBackground(Void... params) {
              // Create an array
              itemlist = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;();
              // Retrieve JSON Objects from the given URL address
              JSONObject jsonobject = JSONfunctions.getJSONfromURL("http://mahatiffin.com/web/selectallmenu.php");
  
              try {
                  // Locate the array name in JSON
                  jsonarray = jsonobject.getJSONArray("AllMenu");
  
                  for (int i = 0; i &lt; jsonarray.length(); i++) {
                      HashMap&lt;String, String&gt; map = new HashMap&lt;String, String&gt;();
                      jsonobject = jsonarray.getJSONObject(i);
                      // Retrive JSON Objects
                      map.put("name", jsonobject.getString("name"));
                      map.put("Description", jsonobject.getString("Description"));
                      map.put("price", jsonobject.getString("price"));
                      map.put("image_path", jsonobject.getString("image_path"));
                      // Set the JSON Objects into the array
                      itemlist.add(map);
                  }
              } catch (JSONException e) {
                  Log.e("Error", e.getMessage());
                  e.printStackTrace();
              }
              return null;
          }
  
          @Override
          protected void onPostExecute(Void args) {
              // Pass the results into ListViewAdapter.java
              adapter = new ListViewAdapter(getActivity(), itemlist);
              // Set the adapter to the ListView
              list.setAdapter((ListAdapter) adapter);
          }
      }
  }
  
  
  public class JSONfunctions {
      public static JSONObject getJSONfromURL(String url) {
          InputStream is = null;
          String result = "";
          JSONObject jArray = null;
  
          // Download JSON data from URL
          try {
              HttpClient httpclient = new DefaultHttpClient();
              HttpPost httppost = new HttpPost(url);
              HttpResponse response = httpclient.execute(httppost);
              HttpEntity entity = response.getEntity();
              is = entity.getContent();
  
          } catch (Exception e) {
              Log.e("log_tag", "Error in http connection " + e.toString());
          }
  
          // Convert response to string
          try {
              BufferedReader reader = new BufferedReader(new InputStreamReader(
                      is, "iso-8859-1"), 8);
              StringBuilder sb = new StringBuilder();
              String line = null;
              while ((line = reader.readLine()) != null) {
                  sb.append(line + "\n");
              }
              is.close();
              result = sb.toString();
          } catch (Exception e) {
              Log.e("log_tag", "Error converting result " + e.toString());
          }
  
          try {
  
              jArray = new JSONObject(result);
          } catch (JSONException e) {
              Log.e("log_tag", "Error parsing data " + e.toString());
          }
  
          return jArray;
      }
  }
  </code></pre>
  
  <p>In may fragment page nothing is showing only blank page will be displayed.</p>
  
  <p>The log output:</p>
  
  <pre><code>&gt;05-18 17:43:11.730 27019-27019/com.androidbelieve.MahaTiffin D/dalvikvm: VFY: replacing opcode 0x6f at 0x0000
      05-18 17:43:11.740 27019-27082/com.androidbelieve.MahaTiffin E/log_tag: Error converting result java.lang.NullPointerException
      05-18 17:43:11.740 27019-27082/com.androidbelieve.MahaTiffin E/log_tag: Error parsing data org.json.JSONException: End of input at character 0 of 
      05-18 17:43:11.770 27019-27082/com.androidbelieve.MahaTiffin W/dalvikvm: threadid=12: thread exiting with uncaught exception (group=0x40e11378)
      05-18 17:43:11.770 27019-27082/com.androidbelieve.MahaTiffin E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
      java.lang.RuntimeException: An error occured while executing doInBackground()
      at android.os.AsyncTask$3.done(AsyncTask.java:299)
      at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
      at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
      at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
      at java.util.concurrent.FutureTas...(FutureTask.java:137)
      at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
      at java.lang.Thread.run(Thread.java:856)
      Caused by: java.lang.NullPointerException
      at com.androidbelieve.MahaTiffin.All_Item_Fragment$ReadJSON.doInBackground(All_Item_Fragment.java:58)
      at com.androidbelieve.MahaTiffin.All_Item_Fragment$ReadJSON.doInBackground(All_Item_Fragment.java:43)
      at android.os.AsyncTask$2.call(AsyncTask.java:287)
      at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
      at java.util.concurrent.FutureTas...(FutureTask.java:137) 
      at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 
      at java.lang.Thread.run(Thread.java:856) 
      05-18 17:43:12.420 27019-27019/com.androidbelieve.MahaTiffin W/FragmentManager: moveToState: Fragment state for Veg_Item_Fragment{415d7030 #1 id=0x7f0c00a0 android:switcher:2131493024:1} not updated inline; expected state 3 found 2
      05-18 17:43:12.530 27019-27104/com.androidbelieve.MahaTiffin E/log_tag: Error in http connection java.net.UnknownHostException: Unable to resolve host "mahatiffin.com": No address associated with hostname
      05-18 17:43:12.540 27019-27104/com.androidbelieve.MahaTiffin E/log_tag: Error converting result java.lang.NullPointerException
      05-18 17:43:12.540 27019-27104/com.androidbelieve.MahaTiffin E/log_tag: Error parsing data org.json.JSONException: End of input at character 0 of 
      05-18 17:43:12.570 27019-27104/com.androidbelieve.MahaTiffin W/dalvikvm: threadid=14: thread exiting with uncaught exception (group=0x40e11378)
      05-18 17:43:12.570 27019-27104/com.androidbelieve.MahaTiffin I/Process: Sending signal. PID: 27019 SIG: 9
  </code></pre>
  
  <p>How do I fix                                                                                       this?</p>