Simon Guest, our resident J2EE interoperability guru, recently wrote a book detailing
a number of interoperability strategies between .NET and J2EE.
He was kind enough to list me in his acknowledgements for the time spent reviewing
and commenting on his work - espeically the data access stuff.
If you want to see first-hand how you can make .NET and J2EE work together within
your environment, go get this book. We've been preaching and living the interoperability
story for some time now.