The massive Oracle v. Google litigation has entered a new phase, as Oracle filed papers (PDF) yesterday saying it will appeal its loss on “fair use” grounds to the US Court of Appeals for the Federal Circuit.

For a brief recap of the case: after Oracle purchased Sun Microsystems and acquired the rights to Java, it sued Google in 2010, saying that Google infringed copyrights and patents related to Java. The case went to trial in 2012. Oracle initially lost but had part of its case revived on appeal. The sole issue in the second trial was whether Google infringed the APIs in Java, which the appeals court held are copyrighted. In May, a jury found in Google’s favor after a second trial, stating that Google’s use of the APIs was protected by “fair use.”

Oracle’s appeal is no surprise, but it will be a long shot. The four-factor “fair use” test is a fairly subjective one, and Oracle lawyers will have to argue that the jury’s unanimous finding must be overturned. There are various ways a jury could arrive at the conclusion that Google was protected by fair use.