Spring annotations @Repository and @Service

There are a few reasons:

1. It's easier to target pointcuts with more specific annotations. Do not underestimate the usefulness of this!
2. The @Repository annotation carries with it some additional functionality: it causes exceptions to be wrapped up as DataAccessExceptions.
3. The @Service annotation may gain additional semantics in the future but it's not happened yet…

The @Repository annotation (introduced in Spring 2.0) and @Service annotation (introduced in Spring 2.5) are specialization of the @Component annotation.

The main advantage of using @Repository or @Service over @Component is that it's easy to write an AOP pointcut that targets, for instance, all classes annotated with @Repository.

Also, the specialized annotations help to clearly demarcate application layers (in a standard 3 tiers application).

I believe that there are two things Spring had in mind when they added these Component annotations.

1. They can be used to specify point cuts across all objects annotated with that sub-component. (All @Repository or all @Service pointcuts)
2. I think Spring also mentioned that they would be adding some future functionality to them. (I have no citation for this, I just think I read this somewhere)