Google CEO Larry Page returned to the witness stand in a San Francisco federal courtroom today, but managed to avoid saying much despite nearly an hour of sustained grilling by Oracle lawyer David Boies.

Boies' questioning was stymied in part by the fact that Judge William Alsup (who is overseeing the case) stopped him from asking Page about certain documents that aren't in evidence yet. But while Page may have avoided saying much today, Alsup made it clear that Oracle will be able to put him back on the stand later in the trial if it so desires.

Today was the third day of trial in the Oracle v. Google showdown, which is scheduled to go for eight weeks. In three separate phases, a jury of 12 men and women is scheduled to decide whether Google is violating copyrights and patents that Oracle purchased when it bought Sun Microsystems a few years ago.

In his testimony today, Page made it clear that he saw a clear difference between the "free Java" that Google had a right to use, and the more elaborate forms of Java it could have used only if it had struck a deal with Sun.

"There's free Java and there's the Java that's Sun's technology," said Page. Google negotiated with Sun to explore the possibility of working together to build Android, but ultimately did the work on its own.

Page studiously answered Boies' questions on his own terms, at times bordering on evasive. On a few occasions Judge Alsup told Page to answer a "yes or no" question more directly. "The e-mail chain here seems kind of random," he said of one document presented to him. Another time he looked at a presentation to Google executives and said it looked like it was "not the right version."

The mainstay of Boies' questioning furthered Oracle's key theme: that Google was an outlier, the only company using Java APIs without getting permission from Sun in the form of a license.

"You do know that Google never got a license from Sun, right?" Boies asked at one point. "I know we worked hard to negotiate a business license with Java," Page said.

At that point, Judge Alsup broke in. "That's a yes or no question," he said. "Is it true that you never got a license?"

"I'm not sure whether we ever got a license," Page said. Shortly afterwards, Boies asked again: "Did Google ever get a license from Sun, or from Oracle, for Java?" "I don't think that we did, no." "Can you name a single company that uses Java APIs that has not taken a license from Sun or Oracle, except for Google?" asked Boies. "I'm not an expert on that and I don't know."

After being curt with Boies, Page opened up more when he was examined by his own lawyer, Robert Van Nest. He explained that Android was developed as a way to get Google services out to mobile phone users in a more standardized way.

"We had been frustrated getting our software out to people," before Android, Page explained. "We had a closet [at Google] full of almost 100 phones, but it was almost impossible to develop through those phones. We primarily thought [Android] was a great way to get our existing services out to people and make them work—search, e-mail, and so on."

Page also described how the company reached an impasse with Sun. It would have been convenient to use Sun's technology and code, and saved Google "time and trouble," he said. But the price was too high. Google went down its own path, Page said.

"We tried hard to negotiate with Sun," he said. "Ultimately the idea we had for Android was a very open source system, and that was in conflict with things like the TCK, where they [Sun] charge money just to test compatibility. We were unable to convince them on that, and a whole bunch of other issues."

Also testifying today was Edward Screven, a Chief Corporate Architect at Oracle. Screven emphasized the importance of APIs to Oracle's business. Screven testified about the importance of Java and its APIs to Sun's business; he also said that Google had "fragmented and forked" Java by releasing Android.

Screven also testified that Java was the most valuable part of Oracle's purchase of Sun. In doing so, Screven mentioned the purchase price: $7.4 billion. Alsup quickly jumped in at that point, telling the jurors to disregard that figure. He said it has "nothing to do" with this case. The judge had previously warned Oracle's lawyers not to try to put "big numbers" in front of the jury. Oracle CEO Larry Ellison testified yesterday about his company's purchase of Sun, but didn't mention the purchase price.