It is not that if you use Struts 2.0 you should use Spring. In general Spring is considered to be used as a candidate wherein the objects that your application would need and their dependencies are managed with ease provided the richness of building a transactional, distributed computing is easily achieved using Spring. Spring offers very good integration with some well known and widely used frameworks like Hibernate, Struts, EJB, JSF and many more. What this integration mean is that you get to use those frameworks also with ease by letting Spring control them.
SCJP 1.4, SCWCD 1.4 - Hints for you, Certified Scrum Master
Did a rm -R / to find out that I lost my entire Linux installation!