This question's been asked before: What's the difference between @Component, @Repository & @Service annotations in Spring?
In Spring 2.0 and later, the @Repository annotation is a marker for
any class that fulfills the role or stereotype (also known as Data
Access Object or DAO) of a repository. Among the uses of this marker
is the automatic translation of exceptions.
Spring 2.5 introduces further stereotype annotations: @Component,
@Service, and @Controller. @Component is a generic stereotype for any
Spring-managed component. @Repository, @Service, and @Controller are
specializations of @Component for more specific use cases, for
example, in the persistence, service, and presentation layers,
respectively.
Therefore, you can annotate your component classes with @Component,
but by annotating them with @Repository, @Service, or @Controller
instead, your classes are more properly suited for processing by tools
or associating with aspects. For example, these stereotype annotations
make ideal targets for pointcuts.
Thus, if you are choosing between using @Component or @Service for
your service layer, @Service is clearly the better choice. Similarly,
as stated above, @Repository is already supported as a marker for
automatic exception translation in your persistence layer.
