Prior to this change, ScheduledAnnotationBeanPostProcessor found any
@Scheduled methods against the ultimate targetClass for a given bean
and then attempted to invoke that method against the bean instance. In
cases where the bean instance was in fact a JDK proxy, this attempt
would fail because the proxy is not an instance of the target class.
Now SABPP still attempts to find @Scheduled methods against the target
class, but subsequently checks to see if the bean is a JDK proxy, and if
so attempts to find the corresponding method on the proxy itself. If it
cannot be found (e.g. the @Scheduled method was declared only at the
concrete class level), an appropriate exception is thrown, explaining to
the users their options: (a) use proxyTargetClass=true and go with
subclass proxies which won't have this problem, or (b) pull the
@Scheduled method up into an interface.
Issue: SPR-8651