The first problem with this library is that it is from Jakarta which means its probably not of production quality and the APIs are subject to dramtic change at the drop of a hat. That (personal) gripe aside, why would you use Jakarta's own library when you could use the new JSTL SQL tags?
In terms of functionality, this library doesn't offer much to developers. It is aimed at smaller, less-mature development teams or even individuals, you could gain much more by looking at http://jdbforms.sf.net (there is also an Onjava article about it). DBForms contains all the functionality to create complete CRUD applications very quickly.