The problem for Google is that "compilations" in copyright law may be considered copyrightable even if the underlying data being compiled is not. The legal requ

The problem for Google is that "compilations" in copyright law may be considered copyrightable even if the underlying data being compiled is not. The legal requirement is that the data needs to be "selected, coordinated, or arranged in such a way that the resulting work as a whole constitutes an original work of authorship". (https://www.bitlaw.com/copyright/database.html https://www.bitlaw.com/copyright/database.html) As an example, individual recipes are generally not copyrightable, but if you compile a set of recipes and publish them in a cookbook, the cookbook itself would be copyrightable. As applied to Java, even if individual method signatures like max/min/split/replace/delete/etc might not be copyrightable, the fact that you've organized those specific methods into specific classes named Math/String/File and then organized those classes into specific packages named java.lang and java.io might meet the threshold for copyrightability as a "compilation". While it would likely not be good for the software industry for reasons discussed in this thread, I would not be particularly surprised if the court ruled in favor of Oracle on this particular subject.