What is the impact of using the @Transactional annotation in a Spring application?

The @Transactional annotation in Spring indicates that a method or class should be executed within a transaction. This means that all database operations within this method will be part of a single transaction, which will either be fully committed or fully rolled back in case of an error.

Main effects of using @Transactional:

• Atomicity: changes are only saved if the entire method succeeds.
• Rollback management: in case of exceptions, the transaction is rolled back.
• Isolation: the transaction isolation level can be configured.
• Propagation management: it can be set how the transaction behaves when calling other transactional methods.

Example:

@Service
public class UserService {

    @Transactional
    public void createUserAndProfile(User user, Profile profile) {
        userRepository.save(user);
        profileRepository.save(profile);
        // If an exception occurs here, both saves will be rolled back
    }
}