Nested transaction on Spring

This is not specifically a problem with @Transactional. It is due to the configuration of your <tx:annotation-driven/>.

Spring uses two different AOP mechanisms: JDK dynamic proxies or CGLIB. JDK dynamic proxies is the default and it works through the use of interfaces at run-time. CGLIB works by generating subclasses at compile-time. If you specify <tx:annotation-driven proxy-target-class="true"/>, Spring will use CGLIB, and your second @Transactional will fire.

You can read more about the subject here.

This behavior is the documented behavior of Spring when using the proxy mode for AOP. It can be changed by switching to the aspectj mode which perform code instrumentation either on compilation or at runtime.