Особенности вызова методов, помеченных @Transactional. Проблема self-вызова.

The @Transactional annotation in Spring manages transactions at the proxy level. When a method annotated with @Transactional is called, Spring creates a proxy that opens a transaction before executing the method and closes it afterward.

Self-invocation problem: If a method within a class calls another method of the same class that is annotated with @Transactional, the call occurs directly, bypassing the proxy. As a result, the transaction will not be applied.

For example:

@Service
public class MyService {

    @Transactional
    public void transactionalMethod() {
        // code within a transaction
    }

    public void caller() {
        transactionalMethod(); // self-invocation, transaction will not work
    }
}

To avoid this problem, you can:

• Extract the transactional method into a separate bean and call it through the Spring context.
• Use AOP or AspectJ for more advanced proxying.
• Call the method through a proxy, for example, by injecting a self-reference via ApplicationContext.

Thus, @Transactional only works when called through a proxy, and self-invocations bypass this mechanism.