In what context and with what level of transaction isolation did you work in your last project?

In my last project, I used transactions in the context of working with a database through the Spring Framework. I typically applied the READ_COMMITTED isolation level to avoid reading uncommitted data (dirty reads), while ensuring good performance. Transactions were managed using the @Transactional annotation at the service layer, which allowed automatic management of transaction start and end.

Example:

@Service
public class UserService {
    @Transactional(isolation = Isolation.READ_COMMITTED)
    public void updateUser(User user) {
        // user update logic
    }
}