Oracle Corp won a legal victory against Google Inc on Friday as a US appeals court decided Oracle could copyright parts of the Java programming language, which Google used to design its Android smartphone operating system.

The case, decided by the US Court of Appeals for the Federal Circuit in Washington, is being closely watched in Silicon Valley. A high-profile 2012 trial featured testimony from Oracle's chief executive, Larry Ellison, and Google CEO Larry Page, and the legal issues go to the heart of how tech companies protect their most valuable intellectual property.

Google's Android operating system is the world's best-selling smartphone platform.
 Oracle sued Google in 2010, claiming that Google had improperly incorporated parts of Java into Android. Oracle is seeking roughly $1 billion on its copyright claims.

A San Francisco federal judge had decided that Oracle could not claim copyright protection on parts of Java, but on Friday the three-judge Federal Circuit panel reversed that ruling. "We conclude that a set of commands to instruct a computer to carry out desired operations may contain expression that is eligible for copyright protection," Federal Circuit Judge Kathleen O'Malley wrote.

Pamela Samuelson, a professor at University of California, Berkeley, School of Law who wrote a brief supporting Google in the case, said the Federal Circuit's decision means software companies now face uncertainty in determining how to write interoperable computer programs that do not violate copyright.

"What we have is a decision that will definitely shake up the software industry," said Samuelson. But Oracle attorney E. Joshua Rosenkranz said the law has always been clear on these issues. "There's nothing at all astounding in what the Federal Circuit did," he said.