I want to get genre id and genre name for specific movie so I am generating this type of query:

http://api.themoviedb.org/3/movie/321612?api_key=xxxxx

and I am getting all the response in my Model class Movie.java but I am getting genre ids and genre name of a specific movie null. I am creating MovieGenre.java class which looks like this:

public class MovieGenres
{
    @SerializedName("id")
    private int id;
    @SerializedName("genre_name")
    private String  genre_name;

    public MovieGenres(int id,String genre_name )
    {
        this.id = id;
        this.genre_name=genre_name;
    }


    public String getGenre_name()
    {
        return genre_name;
    }

    public void setGenre_name(String genre_name)
    {
        this.genre_name = genre_name;
    }

    public int getId()
    {

        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

And Now I am Creating a List variable in the Movie class and Setter and Getter for this variable and the class Movie looks like this:

Movie.java
public class Movie
{
 @SerializedName("movie_genres")
    private List<MovieGenres>movie_genres = new ArrayList<MovieGenres>() ;

Movie(List<MovieGenres> movie_genres)
{
this.movie_genre=movie_genre;
}
public void setMovie_genres(List<MovieGenres> movie_genres)
   {
        this.movie_genres = movie_genres;
    }

 public List<MovieGenres> getMovie_genres()
    {
        return movie_genres;
    }
}

Now the result I am getting is null and I do not want to cache the genres list which is suggested by the API team. So what should I do