Any scope type, which has an associated context (as defined in Chapter 6), is a bean defining annotation

First the container must discover types. The container discovers:
• each Java class, interface or enum deployed in an explicit bean archive, and
• each Java class interface, or enum with a bean defining annotation in an implicit bean archive.

The set of context cannot be enumerated until the AfterBeanDiscovery phase in which extensions register contexts. This creates a chicken-egg problem.