This was supported in DefaultAnnotationHandlerMapping but not in the
RequestMappingHandlerMapping. The specific scenario where this matters
is a controller decorated with a JDK proxy. In this scenario the
HandlerMapping looks at interfaces only to decide if the bean is a
controller. The @Controller annotation is better left (and required)
on the class.
Issue: SPR-9374
Backport-Issue: SPR-9384
Backport-Commit: f61f4a960e
2fa0e63e5a