Have you used the @Transactional annotation in Hibernate? Tell about working with transactions.

The @Transactional annotation in Hibernate (and Spring) is used for managing transactions at the method or class level. It ensures that all database operations within the method are executed within a single transaction.

When using @Transactional:

• The transaction automatically starts when entering the method.
• If the method completes successfully, the transaction is committed.
• If an unchecked exception (runtime exception) occurs, the transaction is rolled back.

This simplifies transaction management and ensures atomicity of operations.

Example:

@Service
public class UserService {

    @Transactional
    public void createUser(User user) {
        entityManager.persist(user);
        // other database operations
    }
}

Important to remember:

• Transactions should be short to avoid resource blocking.
• Inside a transaction, you can work with lazy associations without LazyInitializationException.
• When using @Transactional at the service level, it is better to avoid calls from within the same class (self-invocation), as Spring proxy will not work.

In Hibernate without Spring, transactions are managed manually through Session and Transaction:

Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
try {
    // operations
    tx.commit();
} catch (Exception e) {
    tx.rollback();
} finally {
    session.close();
}