Avik Sengupta writes an interesting article explaining IKVM another interesting choice to allow interoperability between .NET and J2EE
IKVM breaks down the barriers between Java and .NET, probably two of the most significant language platforms of the day. In the sometimes adversarial atmosphere between the two communities, this can be viewed with concern by many Java developers, since the barrier of interoperability against a large installed library base is not longer sufficient to protect your skills. However, one can also see it as an opportunity, increasing the range of target platforms on which the Java programmer may utilize his skills. I think IKVM eventually makes language bigotry the loser, and the winner is that old cliché -- "the right tool for the job."