The revenue-sharing agreement reveals the lengths Google must go to keep people using its search tool on mobile devices. It also shows how Apple benefits financially from Google's advertising-based business model that chief executive Tim Cook has criticised as an intrusion of privacy.

Court showdown

Oracle has been fighting Google since 2010 over claims that the search engine company used its Java software without paying for it to develop Android. The showdown has returned to US District Judge William Alsup in San Francisco after a pit stop at the US Supreme Court, where Google lost a bid to derail the case. The damages Oracle now seeks may exceed $US1 billion since it expanded its claims to cover newer Android versions.

Annette Hurst, the Oracle attorney who disclosed details of the Google-Apple agreement at last week's court hearing, said a Google witness questioned during pretrial information said that "at one point in time the revenue share was 34 per cent." It wasn't clear from the transcript whether that percentage is the amount of revenue kept by Google or paid to Apple.

An attorney for Google objected to the information being disclosed and attempted to have the judge strike the mention of 34 per cent from the record.