Loading / saving objects in a file in Java

Question

I want to save an object from my class in a file, and then load the object from this file. But somewhere, I make a mistake (s) and cannot understand where. Can I get 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));
    }
}

Answer 1

The solution to this problem is that when you use other objects, say a class A, in a type collection HashMapand want to serialize the object HashMap, then the implementinterface Serializablefor the class Aas follows:

class A implements Serializable {
}

...
    HashMap<Integer,A> hmap;
...

Otherwise, this object will not be serialized.

I hope he solves this problem now.

Answer 2

oos.flush() , .

Answer 3

Please remember that the entire object graph is saved during serialization. If you have some references to GUI classes, for example, you must either make them serializable or mark them as "transitional," so Java will not serialize them.