This is an article on the GPL with SUN

QUOTE: "Schwartz singled out the GPL provision that says source code may be mixed with other code only if the other code also is governed by the GPL. That provision is intended to create a body of software that must remain liberated from proprietary constraints. But Schwartz said that some people he's spoken to dislike it because it precludes them from using open-source software as a foundation for proprietary projects."