Class 'Room' is abstract; cannot be instantiated

Question

I have a class an abstract class Room which has subclasses Family and Standard, I have created room = new ArrayList<Room>(); within a Hostel class. I have a method to add a room to the ArrayList;

public String addRoom(String roomNumber, boolean ensuite)
{
    if  (roomNumber.equals("")) 
        return "Error - Empty name field\n";
    else

    room.add( new Room(roomNumber,ensuite) );
    return  "RoomNumber: " + roomNumber + " Ensuite: " + ensuite 
     + "  Has been added to Hostel " + hostelName;
}

However I get the compile time error;

Room is abstract; cannot be instantiated

I understand that abstract classes cannot be instantiated, but what is the best way to add rooms?

Solution 1

You have this error because you are trying to create an instance of abstract class, which is impossible. You have to

room.add(new Family(roomNumber, ensuoute));

or

room.add(new Standard(roomNumber, ensuoute));

Solution 2

The error says it all: Room is an abstract class, and abstract classes cannot be instantiated.

You're trying to instantiate Room here:

new Room(roomNumber,ensuite)

You can only create instances of concrete (i.e. non-abstract) classes. It is likely to be the case that Family and Standard are concrete classes and can therefore be instantiated.

To fix this, you'll need to figure out the correct room type given the room number, and instantiate the appropriate class.

Comments

[Darren Burgess]

thanks, this is exactly what i was looking for, duno how i didnt think of it