When is a bean ready for advised calls?

Goal & mental model verified

A singleton is one instance per bean definition per container. Request scope follows a web request. The container manages initialization/destruction for managed beans, with important exceptions such as prototype destruction.

Worked example · design exercise synthesis

QuoteService may safely be a singleton when it stores only stable collaborators. A mutable currentTenant field would mix simultaneous requests; carry tenant context through an explicit request-level mechanism instead.

Engineering decision synthesis

Keep shared service state immutable or deliberately synchronized. Choose scope by ownership and lifetime; request-scoped dependencies in singletons need appropriate proxies or lookup.

Pitfall & diagnosis synthesis

@PostConstruct runs during initialization, before normal proxy-mediated use. Depending on transactional advice there is unsafe. Prototype cleanup is not automatically managed like singleton destruction.

Improve & validate synthesis

Move external startup work into a suitable lifecycle stage. Test concurrent requests and shutdown; name who owns cleanup for prototype or manually created objects.