quarkus with @NoScope like @Stateless?

Question

What is the quarkus counterpart of a @Stateless EJB?

Actually, I can only make use of cdi within typical cdi beans, but there is no bean with no scope like @Stateless in quarkus, or?

@NoScope // such scope does actually not exit in cdi or quarkus
public class MyBean{

    @Inject 
    EntityManager em;

}

Answer 1

CDI @RequestScopedmeans new instance for each request. It's not keeping the state between requests so you can think it as a replacement for @Stateless.

@Stateless vs @RequestScoped

Answer 2

When we use @RequestScope in a context where we would use @Stateless, we only simulate @Stateless behavior by destroying and creating the bean on every request. The benefit is we enforce isolation between requests; however, the tradeoff is we perform expensive creation / destroying of the bean every request.

If we care about performance and only need stateless behavior without enforcing isolation between requests, we should design our beans as stateless and use @Dependent or @ApplicationScoped scopes. There is no risk of having no isolation between requests if developers are careful and write their code statelessly.

Using @RequestScope as @Stateless sounds like a smelly workaround for a missing feature in the framework; hence I prefer not to use it in this context unless necessary.

Answer 3

EJBs come with additional features like thread pooling, monitoring, or transaction management (when container managed),...

So in Quarkus there is no direct replacement for @Stateless, but you can get close by using @Transactional in combination with @RequestScoped.

I don't know @NoScope, but I guess you meant @Dependent.

Check out Adam Bien's blog: https://www.adam-bien.com/roller/abien/entry/migration_from_stateless_bce_to