title: .NullPointerException while retrieving data with volley
body: <p>i am trying to retrieve data with volley but i keep getting this error:</p>
  
  <p>This is my json file which is accessed with this link "http:/192.168.1.4/pim/get_all_bus.php" where 192.168.1.4 is my local ip address</p>
  
  <pre><code>    {
  "Bus": [
      {
          "id_bus": "3",
          "name_bus": "51A",
          "terminusDepart": "Ennasr1",
          "terminus_arrivee": "TGM"
      },
      {
          "id_bus": "4",
          "name_bus": "51A",
          "terminusDepart": "Ennasr2",
          "terminus_arrivee": "tunis"
      }
  ],
  "success": 1
  }
  </code></pre>
  
  <p>the error that i am getting is this</p>
  
  <pre><code>   04-09 14:40:00.589 5256-5256/info.androidhive.volleyexamples E/AndroidRuntime: FATAL EXCEPTION: main
                                                                             Process: info.androidhive.volleyexamples, PID: 5256
                                                                             java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference
                                                                                 at com.android.volley.Request.&lt;init&gt;(Request.java:136)
                                                                                 at com.android.volley.toolbox.JsonRequest.&lt;init&gt;(JsonRequest.java:58)
                                                                                 at com.android.volley.toolbox.JsonArrayRequest.&lt;init&gt;(JsonArrayRequest.java:42)
                                                                                 at info.androidhive.volleyexamples.JsonRequestActivity.makeJsonArryReq(JsonRequestActivity.java:111)
                                                                                 at info.androidhive.volleyexamples.JsonRequestActivity.onClick(JsonRequestActivity.java:146)
                                                                                 at android.view.View.performClick(View.java:5697)
                                                                                 at android.widget.TextView.performClick(TextView.java:10826)
                                                                                 at android.view.View$PerformClick.run(View.java:22526)
                                                                                 at android.os.Handler.handleCallback(Handler.java:739)
                                                                                 at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                 at android.os.Looper.loop(Looper.java:158)
                                                                                 at android.app.ActivityThread.main(ActivityThread.java:7224)
                                                                                 at java.lang.reflect.Method.invoke(Native Method)
                                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
                                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
  </code></pre>
  
  <p>the function that i am using is this one :</p>
  
  <pre><code>    private void makeJsonArryReq() {
      showProgressDialog();
      JsonArrayRequest req = new JsonArrayRequest("http:/192.168.1.4/pim/get_all_bus.php",
              new Response.Listener&lt;JSONArray&gt;() {
                  @Override
                  public void onResponse(JSONArray response) {
                      Log.d(TAG, response.toString());
  
                          msgResponse.setText(response.toString());
  
  
                      //msgResponse.setText(response.toString());
                      hideProgressDialog();
                  }
              }, new Response.ErrorListener() {
                  @Override
                  public void onErrorResponse(VolleyError error) {
                      VolleyLog.d(TAG, "Error: " + error.getMessage());
                      hideProgressDialog();
                  }
              });
  
      // Adding request to request queue
      AppController.getInstance().addToRequestQueue(req,
              tag_json_arry);
  
      // Cancelling request
      // ApplicationController.getInstance().getRequestQueue().cancelAll(tag_json_arry);
  }
  </code></pre>