What obligations does the @Transactional annotation fulfill in the context of transaction management?

The @Transactional annotation in Java is used for managing transactions at the method or class level. It guarantees the following commitments:

• Atomicity: All operations within a transaction are executed as a single unit — either all succeed or all are rolled back in case of an error.
• Transaction lifecycle management: When entering a method with @Transactional, a transaction begins; upon successful completion — commit; if an exception occurs — rollback.
• Isolation: Ensures a certain level of transaction isolation, preventing issues with concurrent data access.
• Propagation support: Allows defining how the transaction propagates to called methods (e.g., creating a new one or using an existing one).

Example of usage:

@Service
public class UserService {

    @Transactional
    public void createUser(User user) {
        userRepository.save(user);
        // other operations that should be atomic
    }
}

If an exception occurs in the createUser method, all changes will be rolled back.