Google paid Apple a hefty $1 billion in 2014 to keep its search bar as the default iOS search engine, as part of a revenue-sharing deal, Bloomberg reported Thursday. The details emerged in a transcript of court proceedings in an ongoing legal battle between Oracle and Google.

The search engine giant has an agreement with Apple that gives the iPhone maker a percentage of the revenue Google generates through the Apple device, an attorney for Oracle said at a Jan. 14 hearing in a federal court, according to Bloomberg.

There has been plenty of speculation around the highly confidential agreement between Google and Apple, but the companies have never publicly disclosed it. While terms of the contract are unclear, details from the court proceedings showed that Google apparently handed over a percentage of revenue generated through iOS device searches in return for being able to process and mine data from iPhone users. 

Oracle's attorney, Annette Hurst, noted in court last week that an anonymous Google witness interviewed during pretrial proceedings said, "At one point in time the revenue share was 34 percent." It was not immediately clear if the percentage reflects the share Google keeps or pays to Apple.

Google lawyers reportedly attempted to have the witness’ statement regarding the 34 percent share struck off the court transcript. Google filed another request to have the transcript sealed and redacted, and Apple also reportedly requested the same in a separate filing.

Apple CEO Tim Cook has criticized Google’s advertising-based business model, distancing Apple from companies that monetize personal data.

"You might like these so-called free services, but we don't think they're worth having your email, your search history and now even your family photos data mined and sold off for God knows what advertising purpose," Cook said at the Electronic Privacy Information Center's Champions of Freedom event last year. "And we think some day, customers will see this for what it is."

Oracle is entangled in a copyright infringement lawsuit with Google since 2010, over claims that the search engine company used its Java software without paying for it to develop Android. Google's Android operating system has generated revenue of about $31 billion and profit of $22 billion since its release, Hurst told the court, Bloomberg reported.

Oracle is seeking royalties from Google over its use of some of the Java language, while Google argues it should be able to use Java without paying a fee.