What is the default scope for REST resource beans (using @Path annotation) ?

[omasseau]

Let's say I have this :

@Path
public class MyRestResource {
     //...
}

What will be the default scope ?

I cannot really find this information in the documentation, except it says that there will be only a single instance of the REST resource.
Does it mean that the default scope is @ApplicationScoped or @Singleton, as both are single instances ?

Is there any reason to explictitely use one of this scope explicitely ?
Which one is better ?

The documentation says that its better to use @ApplicationScoped : https://quarkus.io/guides/cdi#applicationscoped-and-singleton-look-very-similar-which-one-should-i-choose-for-my-quarkus-application

But I am not sure if it applies to REST resources.

[mkouba]

Does it mean that the default scope is @ApplicationScoped or @singleton, as both are single instances ?

For quarkus-resteasy (RESTEasy Classic), it's controlled by the quarkus.resteasy.singleton-resources config property and it should be @Singleton by default. For quarkus-rest (RESTEasy Reactive, default rest extension), it's @Singleton by default AFAIK. But maybe there are some exceptions? CC @geoand @FroMage.

Is there any reason to explictitely use one of this scope explicitely ?
Which one is better ?
The documentation says that its better to use @ApplicationScoped : https://quarkus.io/guides/cdi#applicationscoped-and-singleton-look-very-similar-which-one-should-i-choose-for-my-quarkus-application
But I am not sure if it applies to REST resources.

Indeed, this recommendation is intended for application developers. Extensions can decide to use @Singleton, for instance to achieve slightly better performance - because there is no indirection, no client proxy that delegates to the current instance from the context. Which makes sense for REST because resources are not regular beans, in the sense that they should not be injected anywhere.

In other words, it does not make sense to add @ApplicationScoped or @Singleton to a rest resource. The only meaningful alternative is to use @RequestScoped in order to create a new instance of the resource per HTTP request.

[geoand]

For quarkus-rest (RESTEasy Reactive, default rest extension), it's @singleton by default AFAIK.

This is absolutely correct