You @Autowire a prototype-scoped bean into a singleton service. Why does each call return the same instance, and how do you fix it?

A singleton is wired once at creation, so the prototype is resolved exactly once and that single instance is captured for the lifetime of the singleton, defeating the prototype scope.

The clean fix is to inject ObjectProvider<MyProtoBean> (or jakarta Provider) and call getObject() per use, which asks the container for a fresh instance each time. Alternatives are method injection via @Lookup, or a scoped proxy; injecting ApplicationContext and calling getBean works but reintroduces the service-locator smell.