What's the difference between how @Component and @Repository / @Service annotations are processed?

Question

I've stumbled upon a rather strange issue today with Spring 3.0:

There's an abstract class A and its concrete implementation A_Impl. A_Impl is annotated as @Repository and is auto-scanned by Spring (<context:component-scan> and <context:annotation-config/> are both declared in context). A and A_Impl are deployed in separate JARs (not sure if that matters). Everything works just fine.

Now, I was reviewing that code and @Repository didn't seem like a good fit semantically (the class in question has nothing to do with persistence) so - in my infinite wisdom - I've decided to change that to more generic @Component. Needless to say, everything blew up leaving me looking like a complete idiot. The error (which occurred during Spring context initialization) was Spring's ClassPathResource.getInputStream() method complaining about A class not being there (it is, I've manually checked; plus regular class loader finds it just fine)

Nothing else has changed. If I swap @Component for @Repository context initializes, if I swap them back it doesn't with the above error. Spring documentation claims there's no difference between @Component and @Repository which is clearly a damned lie :-) So I wonder - what is the difference?

Answer 1

I've been using @Component without troubles.

The only thing (although not-so-intelligent one) that comes to my mind as possibility is that your @Component might not be the spring one. Tapestry, for example, has an annotation named the same way. Other frameworks may also have it. So check your imports.