There is no U.S. law that precisely addresses the question of whether Oracle's Java APIs can be copyrighted, Alsup said in his order. "No law is directly on point. This order relies on general principles of copyright law announced by Congress, the Supreme Court and the Ninth Circuit."

His order applies to the 37 Java APIs at issue in the legal battle between Oracle and Google, he wrote. Still, the reasoning Alsup lays out about the functional nature of APIs could influence future cases involving different software platforms.

"Any decision in any case is specific to the case at hand, the judge would only be ruling on these particular APIs. But that is still a precedent," said Tyler Ochoa, a copyright professor at Santa Clara University School of Law, in an interview before Alsup's order was released.

Ochoa has said he did not think the structure, sequence and organization of Oracle's Java APIs merited protection by copyright, and he said that "existing case law suggests something along those lines."

Whatever Alsup decided, an appeal seemed inevitable. Oracle will now take its case to a higher court to see if it agrees with his order.