[the downside]

[the downside]: "Singletons are evil. Douuuugh. How do you test a singleton ? Worse: how do you test a singleton that requires an HttpServletRequest to initialise ?
Know what is out there! . I can't believe they wrote a Connection pool themselves...
It is good to use a web framework. But it's bad to pick an unknown, buggy, immature framework (sorry...no names here) that was developed by someone who went the 'not invented here' road.
Tight coupling of business logic to the web framework, the Servlet API, the Singletons, the DB, the everything. Again: how do you test this ?
Code to interfaces, not to implementations. I see private ArrayList foo, private HashMap bar all over the place "