public Group getGroupById(Object groupId) { return (groupId != null) ? (Group) idMap.get(groupId) : null; }
public Group getGroupById(Object groupId) { return (Group) ((groupId != null) ? super.getById(groupId) : null); }
    public Group getGroupById(Object groupId)    {        return (groupId != null)                ? (Group) idMap.get(groupId) : null;    }