ServiceGenerator.java

public class ServiceGenerator {

    public static final String BASE_URL = "https://jsonplaceholder.typicode.com";

    private static Retrofit.Builder retrofitBuilder =
            new Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                    .addConverterFactory(GsonConverterFactory.create());

    private static Retrofit retrofit = retrofitBuilder.build();

    private static RequestApi requestApi = retrofit.create(RequestApi.class);

    public static RequestApi getRequestApi(){
        return requestApi;
    }
}