Retrofit is returning an empty body

Question

I'm trying to use retrofit & gson to parse some JSON. However, I am getting an empty response body. When I try to print information from the session object I get a NullPointerException.

I have made sure that the URL is correct and I'm sure my POJOs are correct as well. I am using jsonschema2pojo to help create the POJO classes.

Here is the JSON I'm trying to parse

{
"error": false,
"message": "",
"data": {
    "form": null,
    "session": {
        "id": 8,
        "name_en": "جبر الصمادي",
        "name_ar": "عبداللطيف الجوالدة",
        "mosque_id": 2,
        "teacher_id": null,
        "session_type_id": 2,
        "start_date": "2021-02-13",
        "end_date": "2021-04-14",
        "register_available": 1,
        "brief_en": "Sequi sunt id voluptate eius veniam consectetur temporibus. Officia dolorem repudiandae optio autem iure. Voluptatem impedit eius alias voluptatem a et.",
        "brief_ar": "Error voluptatum est labore ipsam. Quasi beatae quo tenetur quia. Aut rerum hic rerum et quia error reiciendis doloribus. Aut voluptatibus explicabo autem et.",
        "image": "https://via.placeholder.com/640x480.png/00ddcc?text=voluptatem",
        "reason_registry_suspension": "Et dolorum sed voluptas recusandae cum. Odio ut et est vel sunt. Quo molestiae vel et cum odit.",
        "created_at": "2021-01-24T09:05:59.000000Z",
        "updated_at": "2021-01-24T09:05:59.000000Z",
        "mosque": {
            "id": 2,
            "image": "https://via.placeholder.com/640x480.png/00ee22?text=occaecati",
            "name": "عيدالله المومنى",
            "brief_location_description": "Facere natus.",
            "full_location_description": "Provident qui incidunt nobis ut possimus. Qui atque quod dolor iure enim nesciunt. Voluptate quia autem nesciunt.",
            "lat": null,
            "long": null,
            "created_at": "2021-01-24T09:05:58.000000Z",
            "updated_at": "2021-01-24T09:05:58.000000Z"
        }
    }
}
}

This is my retrofit client / setup

 public static Retrofit getClient(){
    Retrofit retrofit = new Retrofit.Builder()
            //.baseUrl("http://api.learn2crack.com/")
            .baseUrl(BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .build();
    return retrofit;
}

Finally, this is the code in my onCreateView

  loginCall.enqueue(new Callback<SessionByIdResponse >() {

        @Override
        public void onResponse(Call<SessionByIdResponse > call, Response<SessionByIdResponse > response) {
            loading.dismiss();
            if (response.isSuccess()) {
                if (response.body().getError()) {
                    Utility.showAlertDialog(context.getString(R.string.error), response.body().getMessage(), context);

                } else {
                    Log.i(TAG, "token: " +  response.body().toString());
                    if (response.body().getData().getForm() !=null){

                    }else {
                        SessionDetails sessionDetails = new 
SessionDetails(response.body().getData().getSession());
                        ((MainActivity)context). 
getSupportFragmentManager().beginTransaction().replace(R.id.frame, sessionDetails).commit();

                    }
                }
            } else {
                Log.i(TAG, response.errorBody().toString());
                Utility.showAlertDialog(context.getString(R.string.error), 
context.getString(R.string.servererror), context);

            }
        }

and here is my model

public class SessionByIdResponse {

@SerializedName("error")
private boolean error;

@SerializedName("message")
private String message;

@SerializedName("data")
private MiddlewareResponse data;

public boolean isError() {
    return this.error;
}

public void setError(boolean error) {
    this.error = error;
}

public String getMessage() {
    return this.message;
}

public void setMessage(String message) {
    this.message = message;
}

 public MiddlewareResponse getData() {
    return data;
}

public void setData(MiddlewareResponse data) {
    this.data = data;
}

public  class MiddlewareResponse {


@SerializedName("form")
private Form form;

@SerializedName("session")
private Session session;

public Form getForm() {
    return form;
}

public void setForm(Form form) {
    this.form = form;
}

public Session getSession() {
    return session;
}

public void setSession(Session session) {
    this.session = session;
}
}

public class Session {


@SerializedName("id")
private int id;
@SerializedName("name_en")
private String name_en;
@SerializedName("name_ar")
private String name_ar;
@SerializedName("mosque_id")
private int mosque_id;
@SerializedName("teacher_id")
private int teacher_id;
@SerializedName("session_type_id")
private int session_type_id;
@SerializedName("start_date")
private String start_date;
@SerializedName("end_date")
private String end_date;
@SerializedName("register_available")
private int register_available;
@SerializedName("brief_en")
private String brief_en;
@SerializedName("brief_ar")
private String brief_ar;
@SerializedName("image")
private String image;
@SerializedName("reason_registry_suspension")
private String reason_registry_suspension;
@SerializedName("created_at")
private String created_at;
@SerializedName("updated_at")
private String updated_at;
@SerializedName("mosque")
// private List<Mosques> mosques;
private  Mosque mosque;

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName_en() {
    return name_en;
}

public void setName_en(String name_en) {
    this.name_en = name_en;
}

public String getName_ar() {
    return name_ar;
}

public void setName_ar(String name_ar) {
    this.name_ar = name_ar;
}

public String getStart_date() {
    return start_date;
}

public void setStart_date(String start_date) {
    this.start_date = start_date;
}

public String getEnd_date() {
    return end_date;
}

public void setEnd_date(String end_date) {
    this.end_date = end_date;
}

public String getUpdated_at() {
    return updated_at;
}

public void setUpdated_at(String updated_at) {
    this.updated_at = updated_at;
}

public String getCreated_at() {
    return created_at;
}

public void setCreated_at(String created_at) {
    this.created_at = created_at;
}

public String getReason_registry_suspension() {
    return reason_registry_suspension;
}

public void setReason_registry_suspension(String reason_registry_suspension) 
{
    this.reason_registry_suspension = reason_registry_suspension;
}

public int getMosque_id() {
    return mosque_id;
}

public void setMosque_id(int mosque_id) {
    this.mosque_id = mosque_id;
}

public int getSession_type_id() {
    return session_type_id;
}

public void setSession_type_id(int session_type_id) {
    this.session_type_id = session_type_id;
}

public int getRegister_available() {
    return register_available;
}

public void setRegister_available(int register_available) {
    this.register_available = register_available;
}

public String getImage() {
    return image;
}

public void setImage(String image) {
    this.image = image;
}

public int getTeacher_id() {
    return teacher_id;
}

public void setTeacher_id(int teacher_id) {
    this.teacher_id = teacher_id;
}

public String getBrief_en() {
    return brief_en;
}

public void setBrief_en(String brief_en) {
    this.brief_en = brief_en;
}

public String getBrief_ar() {
    return brief_ar;
}

public void setBrief_ar(String brief_ar) {
    this.brief_ar = brief_ar;
}

public Mosque getMosque() {
    return mosque;
}

public void setMosque(Mosque mosque) {
    this.mosque = mosque;
}
}

but the messsage is always "" and error is always False and data has MiddlewareResponse but with null session and null form

Answer 1

I guess the teacher_id is not int inside Session , primitives cannot be null , there might be problem parsing the Json, try using it as String and same for Lat and Long inside Mosque , then convert String to int once you parse the response .

Answer 2

the problem was from me I forget to pull the back end code in the serve and the response I post in the question I discover it was from the local host not from the server it took from me three days to discover that