Java.Util.Set does not add new elements

Question

In the store variable when trying to add a new element of type "Store" it always stays with only one element and does not add a new element. And never add a new one. Follow the codes: Metodo main:

public static void main(String[] args) {
        Usuario usuario = new Usuario();
        Set<Integer> idsLojas = new HashSet<>();
        idsLojas.add(123);
        idsLojas.add(333);
        idsLojas.add(3333);

        Set<Loja> lojas = new HashSet<>();
        for (Integer idLoja : idsLojas) {
            lojas.add(new Loja(idLoja));
        }
        usuario.setLojas(lojas);

        System.out.println(usuario.getLojas().size());
    }

Shop builder:

public Loja(Integer id) {
        this.setId(id);

    }

The result is always 1, even if I add 3 values.

Answer 1

Overwrite the methods equals() and hashcode() class Loja. Preferably let your IDE create them for you. When it asks you for which criteria to specify the methods add the store id as criteria.

Read more here: How to define the equality comparison between two objects present in an Arraylist?