Just read from the Hibernate evaluation FAQ and realise that this could be an answer to my concern earlier.
http://www.hibernate.org/263.html
What if JBoss turns evil and creates a commercial fork of Hibernate?
Hibernate is licensed under the terms of the LGPL. The LGPL is different to Apache or BSD style licenses in that it effectively disallows the creation of a closed-source fork. This protects the Hibernate community as well as any contributors to Hibernate. Anyone who wanted to release Hibernate under a different license would have to obtain permission from hundreds of people who have contributed code to Hibernate, which would be impractical. Hibernate is and will be free software.