If you have read my previous post and want to get into the high level technical details of why Oracle thinks it might have a case, read Osvaldo Pinali Doederlein\’s blog on Java.net.
It’s legal and perhaps speaks to why Oracle bought Sun in the first place. They don’t care about the community. They saw the potential ransom they could hold the big companies like Google up for and that was the whole point of buying Sun. They have zero interest in spreading or encouraging the use of Java or its open-source community ideals.