How to create constructor equivalent (is this bad practise)

[eternal lion]

this is my original code (which works):

public class CargoHold extends Room {

    private int maximumCapacity;
    private List<ResourceContainer> resources;

    public CargoHold(RoomTier tier) {
        super(tier);
        this.maximumCapacity = maximumCapacityFinder(tier);
        this.resources = new ArrayList<ResourceContainer>();
    }

[lime violet]

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[eternal lion]

how do i do it properly

to get this

public class CargoHold extends Room {

    private int maximumCapacity;
    private ArrayList<ResourceContainer> resources;

    public CargoHold(RoomTier tier) {
        super(tier);
        this.maximumCapacity = maximumCapacityFinder(tier);
        this.resources = resources;
    }

when i do ^^^ the rest of my code breaks

[tribal kite]

you are assigning resources with itself. You aren't actually initialising it.

[eternal lion]

oh

so how do i initialise it?

is my original code actually correct

[tribal kite]

yeah like you did in your original code

[eternal lion]

ohhh

and is that like, conventionally fine?

and wont cause problems with future code

i thought it would be wrong to have new inside the constructor

[tribal kite]

The entire purpose of the constructor is to make the object functional. It shouldn't have any side effects, meaning it shouldn't change the state of another object but it should do everything needed to put the object in a sort of default state when the object can be used.

[native anchor]

You can just do new ArrayList<>(); btw. The type is already specified in the variable declaration.

If you never want to change the list object, you can also do:

 private int maximumCapacity;
 private final ArrayList<ResourceContainer> resources = new ArrayList<>();