In one sense, Alsup's ruling made Oracle's appeal easier, since the judge agreed that the APIs reflected creativity and originality on the part of their creators. "Now they can concentrate their fire and their arguments on the idea of functionality. That's what they'll do."

Overall, Oracle has a good chance in its appeal, Naughton said. "The cases where you don't have a good shot is where the case turns on the credibility of a witness, a 'he-said, she-said' situation. On a case like this, where it's based on a legal question, they have a fine shot on appeal."

Still, "they're going to have to contend with a thorough, well-written decision by a careful judge and that's not easy," Naughton added.

The ruling is so artfully rendered, in fact, that Oracle will have a tough time winning an appeal, according to Tyler Ochoa, an intellectual-property law professor at the Santa Clara University School of Law.

"This is by far the most careful and well-written opinion on software copyright I've ever read," Ochoa said via email. "I will be astonished if it is not upheld on appeal."