Instead, Schmidt said, Google created a "clean room" version of Java that didn't use Sun's protected code. Its engineers invented "a completely different approach" to the way Java worked internally, Schmidt testified.

"It did not use Sun's intellectual property, as I was told," he said.

"I was very comfortable that what we were doing was legally correct," he testified later.

One of Google's arguments in the case is that Sun knew Google was using Java in Android but never complained or asked it to sign a license. That gave Google an "implied license" for Java, if it needed one at all, according to Google's lawyers.

Schmidt said he used to "meet and chat" with former Sun CEO Jonathan Schwartz every six months, and that Schwartz never raised an issue with Google's Java use.