Retrofit returns content length 0 with spring data rest - heroku

Question

I am using spring boot application with spring data rest deployed on heroku. I have a /api/userDatas end point on which an entity can be created by a POST request. I have tested it using Postman and it gets created.
Now I am using retrofit on android to perform the same functionality. But the problem is that entity gets created on the server but onFailure() always gets called. I have debugged and found that content-length is always 0.
CreateUser
private void createUser() {
Gson gson = new GsonBuilder()
.setLenient()
.create();
HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
logging.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient client = new OkHttpClient.Builder().addInterceptor(logging).build();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(ServeNetworking.ServeURLS.getBaseURL())
.addConverterFactory(GsonConverterFactory.create())
.client(client)
.build();
ServeNetworking serveNetworking = retrofit.create(ServeNetworking.class);
Call<UserData> getUserByIdResponseCall = serveNetworking.socialConnectAPI(userData);
getUserByIdResponseCall.enqueue(new Callback<UserData>() {
#Override
public void onResponse(Call<UserData> call, Response<UserData> response) {
Log.d("getUserById", "onResponse");
Toast.makeText(OTPVerificationActivity.this, "userId : onResponse", Toast.LENGTH_LONG).show();
/**
* Save data in local db and navigate to map screen.
*/
ActivityAnimationUtils.presentActivity(OTPVerificationActivity.this, MapActivity.class);
try{
DBManager.getDBManager(OTPVerificationActivity.this).setIsVerified(true);
} catch (Exception e){
e.printStackTrace();
}
}
#Override
public void onFailure(Call<UserData> call, Throwable t) {
Log.d("getUserById", "onFailure");
Utils.showSnackBar(OTPVerificationActivity.this,"Somethign went wrong", root);
}
});
}
and interface:
public interface ServeNetworking {
#POST("/api/userDatas")
#Headers({ "Content-Type: application/json;charset=UTF-8"})
Call<UserData> socialConnectAPI(
#Body UserData user
);
#GET("/api/userDatas/{userId}")
#Headers({ "Content-Type: application/json; charset=utf-8"})
Call<UserData> getUser(
#Path("userId") String userId
);
/**
* this class is used to get the donor base urls...
*/
class ServeURLS{
private static String baseURL="https://fabrimizer-serve.herokuapp.com";
public static String getBaseURL() {
return baseURL;
}
}
}
I am getting following error:
java.io.EOFException: End of input at line 1 column 1 path $

Answer 1

Found the solution.
added Accept header in ServeNetworking:
#POST("/api/userDatas")
#Headers({ "Content-Type: application/json,"Accept: application/json"})
Call<UserData> socialConnectAPI(
#Body UserData user
);