@Transactional がプライベート Spring Bean メソッドで動作しないのはなぜですか?

public class Bean {
    public void doStuff() {
        doPrivateStuff();
    }

    @Transactional
    private void doPrivateStuff() {

    }
}

When using proxies, you should apply the @Transactional annotation only to methods with public visibility. If you do annotate protected, private or package-visible methods with the @Transactional annotation, no error is raised, but the annotated method does not exhibit the configured transactional settings. Consider the use of AspectJ (see below) if you need to annotate non-public methods.