Employ open source framework to existing web application

Question

Hi everyone,
Existing application model:
MySQL, Tomcat, Java 6 SE, so no EJB.
Own MVC model used (no framework).
Own data access layer model (no framework).
Because this is a corporate application, the UI experience
can not be broken (in terms of new beautifuly deployed pages
vs old existing pages - developed around 8 years ago). Application
run on balanced Tomcats, so it's getting more and more difficult
to synchronize all information.
Question:
Is there a way of smooth transition from own developed MVC
and DAO to open source frameworks to leverage some of the work
required to do manually as it is currently, like validation,
access like hibernate instead of manual creation of DAO objects ... ?
Also, it would be nice to have some reach user interface framework
employed but I don't know how it would be achieved not to break
the look and feel (all pages would have to be done at the same time,
and we are talking here about hundrets of existing screens developed
in different technologies).
Application consists of few millions of lines - so it's a real challange.
Thanks for all tips.

Answer 1

AdrianSosialuk wrote:
Hi everyone,
Existing application model:
MySQL, Tomcat, Java 6 SE, so no EJB.
Own MVC model used (no framework).
Own data access layer model (no framework).
Because this is a corporate application, the UI experience
can not be broken (in terms of new beautifuly deployed pages
vs old existing pages - developed around 8 years ago). What is the exact form of the GUI? Client apps? Html only? what?
Application run on balanced Tomcats, so it's getting more and more difficult
to synchronize all information.
What does that mean? Why are there two of them?
(all pages would have to be done at the same time,
and we are talking here about hundrets of existing screens developed
in different technologies).As a requirement that probably guarantees failure.