User

Entidade

⬇️ Lembrar de criar Getters and Setters + equals&hashcode com ID.

❗Nunca coloque um Set do relacionamento dentro do construtor.

@Entity
@Table(name = "tb_user")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;

    @Column(unique = true, nullable = false)
    private String email;
    private String password;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(
            name = "tb_user_role",
            joinColumns = @JoinColumn(name = "user_id"),
            inverseJoinColumns = @JoinColumn(name = "role_id")
    )
    private Set<Role> roles = new HashSet<>();

    @OneToMany(mappedBy = "users")
    private List<Notification> notifications = new ArrayList<>();

Atualizado