A jury has found that Google breached Oracle's copyright - in theory - by including nine lines of the software giant's Java code in the Android operating system.
However, the ramifications of the finding are as yet unclear, as the jury in the US-based case did not reach agreement on whether this constitutes a 'fair use' of the code, which is Google's principle defence against the infringement lawsuit.
While the jury's findings so far might appear to constitute a victory for Oracle, Google's team have been in celebratory mood, according to court reporters.
Judge Alsup will rule on the key principle of whether APIs are subject to copyright later this month.
A decision in favour of APIs being subject to copyright could have a profound impact on the IT industry, said Internet freedom organisation The Electronic Frontier Foundation yesterday.
"Treating APIs as copyrightable would have a profound negative impact on interoperability, and, therefore, innovation," said a statement on the organisation's website. "APIs are ubiquitous and fundamental to all kinds of program development. It is safe to say that all software developers use APIs to make their software work with other software."
Oracle is suing the search engine giant for $1bn (£619m) over the use of 37 application programming interfaces (APIs) that allow Android's ecosystem of developers to write Java-compatible code.
Since full liability for copyright infringement has not been found, Oracle can only seek statutory damages of up to $150,000 (£93,000).
Google is asking the judge to declare a mistrial - arguably a puzzling decision.
The jury will now hear evidence covering Oracle's allegations that Android violates two Java patents in the next phase of the trial.