@Transactional is implemented via Spring AOP: the container wraps the target bean in a proxy that, for any call to an annotated method arriving from outside the bean, begins a transaction before the method runs, commits it if the method returns normally, or rolls it back if the method throws an unchecked exception — all without the method body containing any explicit transaction-management code itself.

Intermediate5 min

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#@Transactional

It Inherits Every Limitation of Proxy-Based AOP

Because @Transactional relies on the same proxy mechanism as general Spring AOP, it has the identical self-invocation limitation: calling a @Transactional method via `this.method()` from within the same class bypasses the proxy and runs with no transaction at all, silently. It also only works on public methods by default (the proxy can't reliably intercept private/protected methods), which trips people up when they mark a private helper method @Transactional expecting it to take effect.

@Transactional method call → proxy begins transaction → method runs → commit on success / rollback on unchecked exception

Basic @Transactional Usage

java

@Service
class OrderService {
    @Transactional
    void placeOrder(Order order) {
        orderRepository.save(order);
        inventoryService.reserve(order); // same transaction
    }
}