WASHINGTON: US Supreme Court justices peppered lawyers for Google and Oracle with questions on computer code and copyright on Oct 7 in a court clash which could have major ramifications for the technology sector and digital innovation.

Oral arguments were heard in a decade-old legal battle between the two Silicon Valley giants stemming from Oracle's claim that Google illegally copied parts of the Java programming language to develop its Android mobile operating system.

The case revolves around whether copyright protection should be extended to application software interfaces (APIs), or bit of code that allow programs and apps to work together, and if so, whether Google's implementation was a "fair use" of copyrighted material.

In the court session held remotely, Google attorney Thomas Goldstein argued that the practice of reusing software interfaces "is critical to modern interoperable computer software" and allows developers "to write millions of creative applications that are used by more than a billion people."

Goldstein maintained that these APIs were simply a set of instructions for software and were "minimally creative”, thus not eligible for copyright.

He claimed that Oracle's effort would "make computer programming incredibly inefficient," resulting in "fewer creative computer programs."

Joshua Rosenkranz, the attorney arguing for Oracle, said the cases was simply about the theft of 11,000 lines of computer code, which should be under copyright protection as a "creative" work.

Rosenkranz said Google could have paid Oracle a licensing fee or developed its own code as rivals did.

"Microsoft and Apple both spent billion of dollars creating their competing platforms, and that's exactly what the Copyright Act requires," he told the eight justices.

Like restaurant menus?

Chief Justice John Roberts questioned whether the APIs should be considered like restaurant menus which simply organise offerings based on categories.

"You're going to have... appetizers first and entrees and desserts. Now, you shouldn't have to worry about whether that organisation is copyrighted," Roberts said.

But Justice Samuel Alito expressed concern that "under (Google's) argument, all computer code is at risk of losing protection."

Oracle sought US$9bil damages in its original lawsuit, but two separate trials ruled in Google's favour before an appellate court overturned that and called for a new trial.

Goldstein said the top court should defer to the jury decision which concluded that Google's actions were "fair use" of copyrighted material for a "transformative" use.

Google and many Silicon Valley allies have argued that extending copyright to these bits of code would threaten innovation in the fast-evolving digital world.

Software developers have joined Google's petition and others in the tech sector have claimed a win for Oracle could give that company a lock or monopoly on future software. Oracle maintains it is arguing for better rights for software creators, which would be better in the long run for innovation.

The hearing comes amid heightened scrutiny of large technology firms and with Google having seen its fortunes and dominance grow in the online world.

The political overtones are also apparent in light of Oracle founder Larry Ellison's close ties to US President Donald Trump and Google facing antitrust investigations.

The US government filed a brief supporting Oracle, arguing that copyright cannot be taken away from creators simply because it exists in digital format.

Groups representing publishers and authors have sided with Oracle, saying the case could impact copyright protection for other creative works.

The court is likely to make a decision in several weeks or months.

A clear ruling for Google could end the marathon legal battle, while a decision for Oracle could send the case back to lower courts - and a potential retrial.

 - AFP