What is the difference between annotations @Component, @Repository, and @Service in Spring?

These annotations are Spring stereotypes used to mark application components. The difference lies in their semantic purpose and the functionality that Spring can add.

• @Component: A general annotation for any Spring-managed component. Used for general-purpose classes.
• @Repository: Applied to data access layer (DAO) classes. Spring can automatically translate specific data access exceptions (e.g., SQLException) into Spring exceptions (e.g., DataAccessException), simplifying error handling.
• @Service: Used for service layer classes. Although it doesn't add special functionality compared to @Component, it helps in better code organization and explicitly indicates the component's role.

These annotations help Spring understand the application's structure and apply appropriate processing (e.g., transactions for @Repository or @Service).

Example usage:

// General component
@Component
public class GeneralComponent {
    // ...
}

// Data Access Object component
@Repository
public class UserRepository {
    // ...
}

// Service layer component
@Service
public class UserService {
    // ...
}