Can You Use @Component Instead of @Service @Repository?

Direct Answer

@Component is enough for basic component-scan registration and dependency injection. Prefer @Service and @Repository when they accurately describe the class because they communicate intent and can be used by framework infrastructure or aspects. Persistence exception translation requires configured translation infrastructure in addition to @Repository; transaction behavior does not appear merely because a class uses @Service or @Repository.

Code Example

// This works but is architecturally unclear
@Component
public class OrderProcessor {
    private final OrderValidator validator;
    private final OrderDataHandler dataHandler;

    public void processOrder(Order order) {
        validator.validate(order);
        dataHandler.save(order);
    }
}

// Better: semantic clarity and AOP targeting
@Service // Enables transactional pointcuts, communicates intent
public class OrderService {
    private final OrderValidator validator;
    private final OrderRepository repository;

    @Transactional // AOP advice can target all @Service beans
    public void processOrder(Order order) {
        validator.validate(order);
        repository.save(order); // @Repository enables exception translation
    }
}

@Repository // Exception translation active
public class OrderRepository {
    // DuplicateKeyException thrown if order ID exists
}

Common Mistakes & Pitfalls

• Using @Component for everything: Freshers do this because it works, then wonder why exception translation isn't happening or why their AOP logging advice isn't triggering on service methods. The stereotype annotations aren't decorative—they enable features.
• Inconsistent naming conventions: Marking a class UserService but annotating it @Component creates cognitive dissonance for the next developer. Name and annotation should align.
• Ignoring AOP implications: If you use @Component for repositories, you can't write a clean pointcut to add data access logging without also hitting utility beans. Layer-specific annotations let you write surgical AOP advice that targets only the persistence layer or only the service layer.