getApplicationContext()' on a null object reference using volley in non-activity
<p>Take time trying to call a json from android, but the problem is the confusion of context, this is the error returned me</p>

<pre><code>    02-09 19:48:05.494 16350-16350/com.example.cesar.mybankaccess E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.cesar.mybankaccess, PID: 16350
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
at restful.dao.PatronSingleton.getRequestQueue(PatronSingleton.java:37)
at restful.dao.PatronSingleton.&lt;init&gt;(PatronSingleton.java:25)
at restful.dao.PatronSingleton.getInstance(PatronSingleton.java:30)
at restful.dao.Cliente.dologin(Cliente.java:84)
at restful.RestfulOperacional.dologin(RestfulOperacional.java:22)
at com.example.cesar.mybankaccess.view.Login.dologin(Login.java:118)
at com.example.cesar.mybankaccess.view.Login.access$100(Login.java:30)
at com.example.cesar.mybankaccess.view.Login$2.onClick(Login.java:67)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
</code></pre>

<p>I do not get fix, i'm sure is for context getContext or similar, but can't build one</p>

<pre><code>public class RestfulOperacional {
    Cliente cliente;

    public RestfulOperacional() {
        cliente = new Cliente();
    }

    public Object dologin(String s, String s1) {
        return cliente.dologin(s, s1);
    }
}
</code></pre>

<p>And Class on try parse JSON</p>

<pre><code>public class Cliente extends Application {
    private String URL_JSON;
    private static Context context;
    private static Cliente instance = null;

    public Cliente(Context context) {
        this.context = context;
    }

    public Cliente() {

    }


    @Override
    public void onCreate() {
        super.onCreate();
        context = getContext();
    }

    public static Context getContext() {
        return context;
    }
    public static Cliente getInstance(Context context) {
        if (instance == null) {
            instance = new Cliente(context);
        }
        return instance;
    }
    public Cliente dologin(String s, String s1) {
        URL_JSON = Constantes.URL_JSON + Constantes.URL_API_CLIENTE + Constantes.URL_API_CLIENTE_LOGIN;
        // Mapeo de los pares clave-valor
        HashMap&lt;String, String&gt; parametros = new HashMap();
        parametros.put("nif", s);
        parametros.put("claveSeguridad", s1);
        JsonObjectRequest jsArrayRequest = new JsonObjectRequest(
                Request.Method.POST,
                URL_JSON,
                new JSONObject(parametros),
                new Response.Listener&lt;JSONObject&gt;() {
                    @Override
                    public void onResponse(JSONObject response) {
                        Log.i("Json", response.toString());
                        // Manejo de la respuesta
                        //notifyDataSetChanged();
                    }
                },
                new Response.ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                    }
                });
        PatronSingleton.getInstance(getContext()).addToRequestQueue(jsArrayRequest);
        return null;
    }
}
</code></pre>