Resin 3.0.14 to 3.1.0 upgrade

Its been about 2 years since my company has been using Resin without upgrading it. So I finally decided to make the move this week. To my despair, I came across zillions of errors that had to be fixed one by one.
Major culprits for causing all the *big deal* -

1. change in taglib declaration for JSTL core. It has beenc hanged to 'http://java.sun.com/jsp/jstl/core' from 'http://java.sun.com/jstl/core'

2. changes in resin.conf structure

3. JspPrecompileListerner listener class stopped working from 3.0.23 to 3.1.0. Kept throwing a NullPointerException for JspPrecompiler package

4. our Graphing packages required some re-thinking in the way they work

5. calls to retrieve values of variables in the environment context
are no longer allowed to make null calls. The variable should ALWAYS be defined in the environment before you make the call to retrieve its value. Earlier you just got a null value.