Oracle won a US appeals court bid to revive claims that Google copied its Java programming language to develop the Android operating system.
The shortcuts created by Java to perform basic functions like connecting to the Internet are eligible for copyright protection, the US Court of Appeals for the Federal Circuit in Washington ruled on Friday.
The court reinstated a jury's 2012 finding that Google infringed the copyrights, and remanded the case to let Google argue that it had fair use of the technology.
Oracle, the largest database-software maker, had sought more than $1 billion in damages, claiming Google used Java code without paying because it was in a rush to create Android, which has become the world's most popular smartphone platform. The case split the industry between companies that write interface code and those that rely on it to develop software programs.
Software makers Microsoft, NetApp and EMC filed arguments supporting Oracle. Rackspace Hosting, a group of computer scientists and the Application Developers Alliance sided with Google, saying the specific tools in the case are little more than directions without creativity.