Can you list the main characteristics and features of the Spring framework?

Spring is a popular Java framework for building enterprise applications with several key features:

• Inversion of Control (IoC) and Dependency Injection (DI): managing the lifecycle of objects and their dependencies through the Spring container.
• Modularity: a variety of modules for different tasks — Spring MVC for web applications, Spring Data for database operations, Spring Security for security, and others.
• Aspect-Oriented Programming (AOP): allows separation of cross-cutting concerns (logging, transactions) from business logic.
• Transaction support: declarative transaction management.
• Simplified testing: thanks to DI and modularity, writing unit tests is easier.

Example of a simple bean with DI:

@Component
public class UserService {
    private final UserRepository userRepository;

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

    public User findUser(Long id) {
        return userRepository.findById(id);
    }
}