What are the differences between the annotations @Component, @Controller, @Repository, and @Service in Spring, and what are their purposes?

In Spring, the annotations @Component, @Controller, @Repository, and @Service are used to mark classes as beans and serve different purposes:

• @Component — a basic annotation for any Spring component. Used when a class does not fit into other categories.

• @Controller — a specialized component for web controller layers. Handles HTTP requests and returns responses.

• @Service — indicates a service layer where business logic is implemented. Helps separate logic from controllers and repositories.

• @Repository — data access layer. Besides marking, Spring handles database-related exceptions and translates them into its own exceptions.

Thus, these annotations help structure the application into layers and provide Spring with additional information for bean processing.