Google's founder and chief executive, Larry Page, suited up for an appearance in court in San Francisco yesterday in what is shaping up as one of the most significant battles over smartphone patents and copyright and a dramatic showdown between two of the most powerful men in Silicon Valley.
Accused by Oracle boss Larry Ellison of building Google's Android smartphone operating system on the back of his company's intellectual property, Mr Page said he had little knowledge of the internal discussions over whether it needed to get a licence to use Oracle's Java programming language.
Mr Page's appearance came directly after Mr Ellison himself testified on Tuesday, when he called Android a "cheap knock-off".
Android's Java-based software is installed in 300 million mobile devices around the world, and Oracle is claiming $1bn in licensing fees and damages from Google.
In one exchange yesterday morning, Oracle's lawyer, David Boies, asked Mr Page: "Would it have been a violation of Google policy for Google engineers to copy copyrighted materials of other companies?"
Mr Page responded that Google was "very careful about what information we used and what we did not use", and added: "Again, as I said yesterday, I think we did nothing wrong."
In another exchange, Mr Page disputed the notion that Android was critical to Google, but said he wouldn't be surprised if Google's board was told that Android is critical to the company.
Oracle offers Java – invented by Sun Microsystems, which it acquired in 2009 – on an open source basis, but while it is free to developers for some uses, it requires a licence in others. Because of the complexity of those licensing rules and the complexity of the computer code behind Android, the trial is expected to last eight weeks.
Google won some pre-trial tussles and had several Oracle patents struck out; it says damages would amount to less than $100m, even if it lost.
Oracle has presented documents showing Android developers discussing whether they may need a licence, and debating the risk of a legal showdown over the issue.
Mr Page smiled and made eye contact with jurors as he gave testimony; Mr Ellison engaged more directly, and in more detail, with attorneys. "If people could copy our software and create cheap knock-offs of our products, we wouldn't get paid for our engineering and wouldn't be able to invest what we invest," he said.