When does Spring roll back a @Transactional method?

I distinguish a business rejection that should not write anything, an expected alternative result that may commit deliberate state, and an infrastructure failure with an unknown outcome. Some failures surface only during flush or commit after method logic appears complete, so API code must not promise success prematurely. A team can adopt a broader rollback convention, but it should be explicit and consistent. Narrow local exceptions to that convention remain easier to review than relying on individual memory.