EJB, Hibernate, auto save when object.setProperty in service

Question

In my project i have this architecture:

Controller -> Service -> Repository -> DB(oracle).

1. Controller -> View rules
2. Service -> Business rules
3. Repository -> DataBase rules.

When i change de attribute of my object in Service, my project execute update automatically. This is wrong, because i have to call my repository to save!!!

I show my example:

@RequestScoped @ApplicationScoped
public class HomeController { //this is my controller

    private List<Banner> banners;

        @EJB
    private IBannerService bannerService;

        @PostConstruct
    public void init() {
        try {
            this.banners = this.bannerService.buscarBanners(TipoBanner.HOME);
        } catch (Exception e) {
            e.printStackTrace();
            loggerApp(ModuloTipo.PORTAL, LogTipo.ERROR, getNomeUsuarioLogado(), PortalAcaoLog.INIT_ERRO, "erro ao abrir home");
        }
    }


}

My Controller calls my Service.

@Stateless(name = "BannerService")
@Remote(IBannerService.class)
public class BannerService implements IBannerService { //this is my service

    @EJB
    private IBannerRepository bannerRepository;

    @Override
    public List<Banner> buscarBanners(TipoBanner tipo) {
              List<Banner> bannersLink = this.bannerRepository.buscarBanners(tipo);

        for(Banner b : bannersLink) {
            System.out.println(b.getDescricao());
            b.setDescricao(b.getDescricao() + " - this is a test"); //when i do this, automatically save my object 0.o... i don`t now what is happening.
        }
        return bannersLink;
    }

        @Override
    public void salvar(Banner banner) {
        this.bannerRepository.update(banner); //when i want to save, i call this method
    }
}

And this is my repository:

@Stateless(name = "BannerRepository")
@Local(IBannerRepository.class)
public class BannerRepository implements IBannerRepository {

        @PersistenceContext
    private EntityManager entityManager;

       @Override
    public void update(Object object) {
        this.entityManager.merge(object);
    }
}

Answer 1

The default behavior for a JPA EntityManager is to flush and commit in the end of any transaction it participates - being it a normal PersistenceContext (your case) or an extended one.

Also, the default behavior for an EJB is to be transactional on all public methods (with propagation REQUIRED), meaning it will create a transaction if one does not exists.

Your property changes are committed every time because there's a transaction every time on your BannerService (it's an EJB).

I would suggest annotating the buscarBanners() method on BannerService with @TransactionAttribute(TransactionAttributeType.SUPPORTS)