RetrofitNull.java

//MODULE
    @Provides
    @PerActivity
    public Retrofit provideRetrofit(Gson gson, OkHttpClient okHttpClient) {
        Retrofit retrofit = new Retrofit.Builder()
                .addConverterFactory(GsonConverterFactory.create(gson))
                .baseUrl(BASE_URL)
                .client(okHttpClient)
                //converts Retrofit response into Observable
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .build();
        return retrofit;
    }


//COMPONENT
@PerActivity
@Component(modules = {PresenterModule.class, UserLoginModule.class, ResponseModule.class, RetrofitModule.class})
public interface MainComponent {

    void injectIntoMainActivity(MainActivity mainActivity);
    //void injectIntoMainPresenter(MainPresenter mainPresenter);
}