I want to store an object from my class in file, and after that to be able to load the object from this file. But somewhere I am making a mistake(s) and cannot figure out where. May I receive some help?

public class GameManagerSystem implements GameManager, Serializable {

    private static final long serialVersionUID = -5966618586666474164L;
    HashMap<Game, GameStatus> games;
    HashMap<Ticket, ArrayList<Object>> baggage;
    HashSet<Ticket> bookedTickets;
    Place place;


    public GameManagerSystem(Place place) {
        super();

        this.games = new HashMap<Game, GameStatus>();
        this.baggage = new HashMap<Ticket, ArrayList<Object>>();
        this.bookedTickets = new HashSet<Ticket>();
        this.place = place;
    }
    public static GameManager createManagerSystem(Game at) {
        return new GameManagerSystem(at);
    }

    public boolean store(File f) {
        try {
            FileOutputStream fos = new FileOutputStream(f);
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(games);
            oos.writeObject(bookedTickets);
            oos.writeObject(baggage);
            oos.close();
            fos.close();
        } catch (IOException ex) {
            return false;
        }
        return true;
    }
    public boolean load(File f) {
        try {
            FileInputStream fis = new FileInputStream(f);
            ObjectInputStream ois = new ObjectInputStream(fis);
            this.games = (HashMap<Game,GameStatus>)ois.readObject();
            this.bookedTickets = (HashSet<Ticket>)ois.readObject();
                this.baggage = (HashMap<Ticket,ArrayList<Object>>)ois.readObject();
            ois.close();
            fis.close();
        } catch (IOException e) {
            return false;
        } catch (ClassNotFoundException e) {
            return false;
        }
        return true;
    }
.
.
.
}


public class JUnitDemo {

    GameManager manager;

    @Before
    public void setUp() {
        manager = GameManagerSystem.createManagerSystem(Place.ENG);
    }

    @Test
    public void testStore() {
        Game g = new Game(new Date(), Teams.LIONS, Teams.SHARKS);
        manager.registerGame(g);
        File file = new File("file.ser");
        assertTrue(airport.store(file));
    }
}