We are planning to add an enhancement to a existing old Servlet/Jsp application which was developed more than 10yrs back. Is it possible to implement Spring in part of that application with new enhancement? how feasible it would be ? please correct me or guide me if i have wrong idea on this. Thanks in advance
It is quite possible. Heck, you can even add JSF to an old web application. The functionality you are gaining comes as additional services not as something that will conflict with older stuff.
I have a project, in fact, that was done with a proprietary MVC and ORM service and I've been slowly migrating stuff as enhancement requests came it. The only real issue I have with this legacy code co-existing with my newer Spring/JSF code is that the old ORM's entity classes couldn't simply be annotated into JPA entity classes because the old ORL did some questionable things with its objects (they're not POJOs, for one thing). So I occasionally have to transfer stuff between new and old ORM models. Which isn't a Spring issue. Even if I was using JPA without Spring, the modelling confllcts would still exist.
I'm going to be a "small government" candidate. I'll be the government. Just me. No one else.