Alphabet Inc.’s (GOOGL) Google might not get away with using Oracle Corp.’s (ORCL) Java development platform free of charge after all.

On Tuesday, the U.S. Court of Appeals reversed a 2016 July verdict, ruling that Google had in fact violated the fair-use provision of copyright law when it used lines of Oracle's Java code to build its Android operating system. The case, which was first filed in 2010, will now be sent back to a federal court in San Francisco, California to determine how much Alphabet should pay.

Java, one of the most popular programming languages in use today, was developed by Sun Microsystems, which was acquired by Oracle in 2010. Oracle had previously sought $9 billion in damages to compensate for Google not paying it any royalties. Google, which uses Java to design the Android operating system that powers most of the world’s smartphones, continues to insist that the platform is marketed as being free to use.

Google expressed its disappointment at the latest ruling, warning that the courts finding will have a detrimental impact on its many users. “We are disappointed the court reversed the jury finding that Java is open and free for everyone,” Google spokesman Patrick Lenihan said in a statement. “This type of ruling will make apps and online services more expensive for users.”

According to the Financial Times, the Menlo Park, California-based company now plans to launch an appeal to the Supreme Court.

Is Java Free?

If upheld, Tuesday’s ruling will have far-reaching implications for the software industry. In an interview with Reuters, Annemarie Bridy, a professor of intellectual property at the University of Idaho College of Law, warned that Oracle’s latest victory could trigger a wave of other copy infringement cases, impacting the ability of developers to bring new software to market.

“This is a ruling that could have a significant chilling effect on software developers,” she said, adding that companies such as Google rely on computer code from the likes of Oracle to make apps that communicate with each other.

Oracle’s application programming interfaces are free to use for those wanting to build apps for computers and mobile devices. However, during the case, the company said those wishing to use them for a competing platform or to embed them in an electronic device should be forced to pay compensation.

“The fact that Android is free of charge does not make Google’s use of the Java API packages non-commercial,” the three-judge Federal Circuit panel in Washington ruled, according to Bloomberg, adding that Android had generated more than $42 billion in revenue from advertising. (See also: Oracle's Plan To Beat Amazon, Microsoft On Cloud.)

The judges also ruled that Google had not made any changes to the copyrighted material. (See also: France to Sue Apple, Google for 'Abusive Trade Practices'.)

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