The 6-2 ruling, which overturns a victory for Oracle, marks a climax to a decade-old case that divided Silicon Valley and promised to reshape the rules for the software industry. Oracle was seeking as much as $9 billion.

Alphabet extended gains on the news, rising 2.7% as of 10:14 a.m. in New York. Oracle was up 1.7%.

The court said Google engaged in legitimate “fair use” when it put key aspects of Oracle’s Java programming language in the Android operating system.

Writing for the court, Justice Stephen Breyer said Google used “only what was needed to allow users to put their accrued talents to work in a new and transformative program.”

Justices Clarence Thomas and Samuel Alito dissented. Justice Amy Coney Barrett didn’t take part in the case, which was argued before she joined the court.

Each side contended the other’s position would undercut innovation. Oracle said that without strong copyright protection, companies would have less incentive to invest the large sums needed to create groundbreaking products. Google said Oracle’s approach would discourage the development of new software that builds on legacy products.

Oracle said the Supreme Court’s ruling means “the Google platform just got bigger and market power greater. The barriers to entry higher and the ability to compete lower.”

“They stole Java and spent a decade litigating as only a monopolist can,” the company said. “This behavior is exactly why regulatory authorities around the world and in the United States are examining Google’s business practices.”

Programming Short Cuts

Google called the decision “a victory for consumers, interoperability, and computer science.”

“The decision gives legal certainty to the next generation of developers whose new products and services will benefit consumers,” Google’s chief legal officer Kent Walker, said in a statement.

The Computer & Communications Industry Association, whose members include Google, called the ruling “a win for interoperability, copyright principles and the future of innovation.”

“The high court’s decision that fair use extends to the functional principles of computer code means companies can offer competing, interoperable products,” CCIA President Matt Schruers said in a statement.

At issue were pre-written directions known as application program interfaces, or APIs, which provide instructions for such functions as connecting to the internet or accessing certain types of files. By using those shortcuts, programmers don’t have to write code from scratch for every function in their software, or change it for every type of device.

Oracle said the Java APIs were freely available to those who wanted to build applications that run on computers and mobile devices. But Oracle said it required companies to get a license if they wanted to use the shortcuts for a competing platform or to embed them in an electronic device.

The Supreme Court didn’t address whether the code was eligible for copyright protection, an early point of contention. Instead, Breyer said that for this case the court would “assume, for argument’s sake, that the material was copyrightable.”

That approach drew criticism from Thomas, who said in his dissenting opinion that the majority opinion is “wholly inconsistent with the substantial protection Congress gave to computer code.”

Existential Threat

Oracle said Google was facing an existential threat because its search engine—the source of its advertising revenue—wasn’t being used on smartphones. Google bought the Android mobile operating system in 2005 and copied Java code to attract developers but refused to take a license, Oracle contended.

Breyer said that, though Google copied 11,500 lines of code, Google engineers wrote millions more.

“Google, through Android, provided a new collection of tasks operating in a distinct and different computing environment,” Breyer wrote. “Those tasks were carried out through the use of new implementing code (that Google wrote) designed to operate within that new environment.”

Google argued that software interfaces are categorically ineligible for copyright protection. Google also contended that a federal appeals court restricted the fair-use defense so much as to make it impossible for a developer to reuse an interface in a new application. The appeals court decision reversed a jury finding that Google’s copying was a legitimate fair use.

Google argued that software interfaces are categorically ineligible for copyright protection. Google also contended that a federal appeals court restricted the fair-use defense so much as to make it impossible for a developer to reuse an interface in a new application. The appeals court decision reversed a jury finding that Google’s copying was a legitimate fair use.

Tech companies including Mozilla Corp., Microsoft Corp., and International Business Machines Corp. supported Google. Media and entertainment businesses, which rely on strong copyright standards, backed Oracle, as did the Trump administration when the case was argued in October.

Oracle initially sued Google for copyright infringement in 2010. Since then, the case has worked its way up and down the legal system, spurring two jury trials and numerous appeals.

The case is Google v. Oracle America, 18-956.

—With assistance from Naomi Nix.