java.lang.IllegalStateException: Unregistered type class java.util.ArrayList

[Ilya]

I'm seeing this error when trying to save/update an object.

I have an entity called Season.

In each Season, there are a list of Game objects

Season.java

@Parent List<Game> games;

Game.java

@Child Season season;

I am trying to add a new game to the season using this code.

List<Game> games = season.getGames()==null?new ArrayList<Game>():(ArrayList<Game>) season.getGames(); 

games.add(new Game(date, wId, ds.load(Member.class, wId).getName(), league, season, scores));

season.setGames(games);

ds.update(season);

It's odd that the error is saying i haven't registered the ArrayList.

Thanks,

Ilya