title: getApplicationContext()' on a null object reference
body: <pre><code>package com.monishn.android.volley;
  
  import android.content.Context;
  import android.support.v7.app.AppCompatActivity;
  import android.os.Bundle;
  import android.app.Activity;
  import android.app.ProgressDialog;
  import android.os.Bundle;
  import android.util.Log;
  import android.view.View;
  import android.widget.Button;
  import android.widget.TextView;
  import android.widget.Toast;
  import com.android.volley.Response;
  import com.android.volley.VolleyError;
  import com.android.volley.VolleyLog;
  import com.android.volley.toolbox.JsonArrayRequest;
  import com.android.volley.toolbox.JsonObjectRequest;
  import org.json.JSONArray;
  import org.json.JSONException;
  import org.json.JSONObject;
  
  public class MainActivity extends AppCompatActivity {
  
      // json array response url
      private String urlJsonArry = "www.shaoniiuc.com/my_json";
  
      private static String TAG = MainActivity.class.getSimpleName();
      private Button btnMakeObjectRequest, btnMakeArrayRequest;
  
      // Progress dialog
      private ProgressDialog pDialog;
  
      private TextView txtResponse;
  
      // temporary string to show the parsed response
      private String jsonResponse;
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          btnMakeArrayRequest = (Button) findViewById(R.id.btnArrayRequest);
          txtResponse = (TextView) findViewById(R.id.txtResponse);
          pDialog = new ProgressDialog(this);
          pDialog.setMessage("Please wait...");
          pDialog.setCancelable(false);
  
          btnMakeArrayRequest.setOnClickListener(new View.OnClickListener() {
  
              @Override
              public void onClick(View v) {
  // making json array request
                  makeJsonArrayRequest();
              }
          });
  
      }
  
      /**
       * Method to make json array request where response starts with [
       * */
      private void makeJsonArrayRequest() {
  
          showpDialog();
  
  
          JsonArrayRequest req = new JsonArrayRequest(urlJsonArry,new Response.Listener&lt;JSONArray&gt;(){
  
                      @Override
                      public void onResponse(JSONArray response) {
                          Log.d(TAG, response.toString());
  
                          try {
                              // Parsing json array response
                              // loop through each json object
                              jsonResponse = "";
                              for (int i = 0; i &lt; response.length(); i++) {
  
                                  JSONObject person = (JSONObject) response.get(i);
  
                                  String id = person.getString("id");
                                  String name = person.getString("name");
  
                                  jsonResponse += "Name: " + name + "\n\n";
                                  jsonResponse += "Id: " + id + "\n\n";
  
                              }
                              txtResponse.setText(jsonResponse);
  
                          } catch (JSONException e) {
                              e.printStackTrace();
                              Toast.makeText(getApplicationContext(), "Error: " + e.getMessage(), Toast.LENGTH_LONG).show();
                          }
  
                          hidepDialog();
                      }
              }, new Response.ErrorListener() {
              @Override
              public void onErrorResponse(VolleyError error) {
                  VolleyLog.d(TAG, "Error: " + error.getMessage());
                  Toast.makeText(getApplicationContext(),error.getMessage(), Toast.LENGTH_SHORT).show();
                  hidepDialog();
              }
          });
  
  // Adding request to request queue
          AppController.getInstance().addToRequestQueue(req);
      }
  
      private void showpDialog() {
          if (!pDialog.isShowing())
              pDialog.show();
      }
  
      private void hidepDialog() {
          if (pDialog.isShowing())
              pDialog.dismiss();
      }
  }
  </code></pre>
  
  <p>Logcat data</p>
  
  <pre><code>08:59:19.981 27919-27919/com.monishn.android.volley E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
                                                                                      at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:107)
                                                                                      at com.monishn.android.volley.AppController.getRequestQueue(AppController.java:33)
                                                                                      at com.monishn.android.volley.AppController.addToRequestQueue(AppController.java:46)
                                                                                      at com.monishn.android.volley.MainActivity.makeJsonArrayRequest(MainActivity.java:107)
                                                                                      at com.monishn.android.volley.MainActivity.access$000(MainActivity.java:23)
                                                                                      at com.monishn.android.volley.MainActivity$1.onClick(MainActivity.java:53)
                                                                                      at android.view.View.performClick(View.java:5207)
                                                                                      at android.view.View$PerformClick.run(View.java:21168)
                                                                                      at android.os.Handler.handleCallback(Handler.java:746)
                                                                                      at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                      at android.os.Looper.loop(Looper.java:148)
                                                                                      at android.app.ActivityThread.main(ActivityThread.java:5443)
                                                                                      at java.lang.reflect.Method.invoke(Native Method)
                                                                                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
                                                                                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
      03-22 08:59:21.847 27919-27919/com.monishn.android.volley 
  </code></pre>