Top 10 Questions of @Transactional annotation in Spring

What does @Transactional do in Spring?
It manages transactions automatically, ensuring data consistency by committing or rolling back operations.

Where can @Transactional be applied?
It can be applied to methods or classes, typically in service-layer components.

What is the default propagation behavior of @Transactional?
The default propagation is REQUIRED, creating a new transaction or joining an existing one.

How does @Transactional handle rollbacks?
It rolls back on unchecked exceptions (e.g., RuntimeException) by default, unless specified otherwise.

Can @Transactional be used with private methods?
No, it works only on public methods due to Spring's proxy-based mechanism.

What is the readOnly attribute in @Transactional?
readOnly=true optimizes for read-only operations, preventing unnecessary transaction overhead.

How does the isolation attribute work in @Transactional?
It defines transaction isolation levels, like DEFAULT, to control data visibility during transactions.

What happens if @Transactional is used without a transaction manager?
Spring throws an exception if no transaction manager is configured for the application context.

Can @Transactional be nested?
Yes, but nested behavior depends on the propagation setting, like NESTED or REQUIRED.

How does @Transactional interact with Spring Boot?
Spring Boot auto-configures a transaction manager, enabling seamless use of @Transactional.