retrofit2_example_MainActivity(OnNetworkCallbackListener).java

OnNetworkCallbackListener networkCallbackListener = new OnNetworkCallbackListener() {
    @Override
    public void onResponse(User user, Retrofit retrofit) {
        //200

    }

    @Override
    public void onBodyError(ResponseBody responseBodyError) {
        //404 (error not null)
        
    }

    @Override
    public void onBodyErrorIsNull() {
        //404 (error is null)       

    }

    @Override
    public void onFailure(Throwable t) {
        //fail any course
       
    }
};