Retrofit POJO is null but JSON is valid

Question

Have been scratching my head on this one. The JSON Response is a valid one:

{
    "MRData": {
        "xmlns": "http://ergast.com/mrd/1.4",
        "series": "f1",
        "url": "http://ergast.com/api/f1/current/2.json",
        "limit": "30",
        "offset": "0",
        "total": "1",
        "RaceTable": {
            "season": "2014",
            "round": "2",
            "Races": [
                {
                    "season": "2014",
                    "round": "2",
                    "url": "https://en.wikipedia.org/wiki/2014_Malaysian_Grand_Prix",
                    "raceName": "Malaysian Grand Prix",
                    "Circuit": {
                        "circuitId": "sepang",
                        "url": "http://en.wikipedia.org/wiki/Sepang_International_Circuit",
                        "circuitName": "Sepang International Circuit",
                        "Location": {
                            "lat": "2.76083",
                            "long": "101.738",
                            "locality": "Kuala Lumpur",
                            "country": "Malaysia"
                        }
                    },
                    "date": "2014-03-30",
                    "time": "08:00:00Z"
                }
            ]
        }
    }
}

The POJO for the response:

public class ApiResponse {
    MRData mrdata;

    public class MRData {
        String xmlns;
        String series;
        String url;
        String limit;
        String offset;
        String total;
        RaceTable raceTable;
    }
}

The apiResponse object is always null. Anyone can point out what is wrong with the POJO object here? Thanks.

Answer 1

I see a couple of potential issues here:

1. You are defining a class inside another class; I have never seen it done like this. You might want to separate in two different files.

2. Your variable names on your POJO should match the variable names on the JSON response exactly. For example:

public class ApiResponse {MRData MRData;}

If you want your POJO's variables to be different than what the JSON sends back, you should use @SerlizedName.