What is the role of the inversion of control principle in the context of Spring Framework?

The Inversion of Control (IoC) principle in the Spring Framework means that the creation and wiring of objects are delegated to the Spring container, rather than being implemented manually in the code. This allows for separation of configuration and dependency management from business logic, making testing and maintenance easier.

Instead of creating objects directly, the developer describes dependencies, and Spring injects them automatically (via Dependency Injection). For example, a class does not create its dependencies but receives them from outside.

Example of dependency injection through constructor in Spring:

@Component
public class UserService {
    private final UserRepository userRepository;

    @Autowired
    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    // business methods
}

Here, Spring will automatically create and pass the required UserRepository when creating UserService.