Not getting photos links when parsing Facebook graph API request on android

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Mobile

Android

Facebook-API

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I'm trying to get user photos link on android using Facebook SDK 4.0 and graph API.
I wrote this code to parse and get photos link -

new GraphRequest(

                AccessToken.getCurrentAccessToken(),
                        "/" + userId + "/photos",
                        null,
                        HttpMethod.GET,
                        new GraphRequest.Callback() {
                            public void onCompleted(GraphResponse response) {

                                json = response.getJSONObject();

                                try {
                                    jarray = json.getJSONArray("data");

                                } catch (JSONException e) {
                                    e.printStackTrace();
                                }

                                for(int i = 0; i < jarray.length(); i++){

                                    try {
                                        URL1 = json.getString("url");
                                        info.setText(URL1.toString());
                                        Log.d("got URLSSSs", URL1.toString());
                                    } catch (JSONException e) {
                                        e.printStackTrace();
                                    }

                                }
                            }
                        }
                ).executeAsync();

But its neither showing any error nor getting any URLs/links. Can anyone tell whats wrong here ?