A US appeals court has ruled that Google infringed on Oracle's Java programming language when developing its Android operating system.
The ruling, the latest chapter of a court battle that began four years ago, could see the search engine giant forced to pay out up to $1bn in damages.
Oracle originally sued Google in 2010 for copying 37 Java application programming interfaces (APIs) in the latter's Android operating system, although a US district court in San Jose ruled the APIs were not copyrighted in 2012.
However last Friday the US Court of Appeals for the Federal Circuit in Washington overturned the district court's judgment, and found Google guilty of copyright infringement.
"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 said of the verdict.
"We find that the district court failed to distinguish between the threshold question of what is copyrightable -- which presents a low bar -- and the scope of conduct that constitutes infringing activity."
The judges are yet to rule, however, on Google's defence that the APIs that it used in Android fall under the Fair Use Doctrine.
Experts believe that the verdict is likely to have a far reaching effect, and may open the gates for many such cases in Silicon Valley.
University of California School of Law professor Pamela Samuelson, who wrote a brief for Google, told Reuters that 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.
Google reacted to the verdict by saying, "We're disappointed by this ruling, which sets a damaging precedent for computer science and software development, and are considering our options."