Oracle overpaid for Sun for a reason, which was something of a mystery. It now appears that collecting royalties on Java used in non-GPL applications might have been the reason. http://arstechnica.com/tech-policy/news/2010/08/oracle-sues-google-over-use-of-java-in-android-sdk.ars

The reason, in case you've not delved into FOSS licenses, is that any application using a component licensed under the GPL main license must itself be licensed under the main GPL license. Otherwise you pay for a commercial license, in this case to finance Larry Ellison's next boat.

.Net looks good by comparison, especially given the availability of Mono. http://tirania.org/blog/archive/2010/Aug-13.html

Amazing.

Hank