SAN FRANCISCO—Oracle CEO Safra Catz took the stand in federal court today as her company makes its case that Google should pay billions of dollars for using 37 Java APIs in its Android operating system.

Oracle, which acquired Java when it purchased Sun Microsystems, sued Google over the APIs in 2010. In 2012, a judge ruled that APIs can't be copyrighted at all, but an appeals court disagreed. Now Oracle may seek up to $9 billion in damages, while Google is arguing that its use of the 37 APIs constitutes "fair use."

Catz, who is co-CEO together with Mark Hurd, began by running through the basics of her background. Born in Israel, she moved to the US with her parents in 1967 and became an American citizen in 1972. She joined Oracle in 1999 and rose through the ranks to become president, the role she had during the 2012 trial against Google. Questioned by Oracle attorney Annette Hurst, Catz explained how her company reached the decision to purchase Sun Microsystems.

"When the Internet bubble imploded in 2001, a number of companies began to have problems," Catz explained. "Some recovered, and some didn't." She continued:

Sun Microsystems, by 2005 and 2006, was having some problems. There was a new CEO with a new strategy that was very unsuccessful. We were concerned there would be issues with funding Java, and Java was absolutely critical for our platform, our products. We did a very fast due diligence, and we actually outbid IBM and agreed with Sun that we would acquire them.

In the company's view, "Java was the single most important asset Oracle ever acquired," Catz said. "We intended to invest in it and bring the Java community together and come out with new versions of Java."

"Did you buy Sun because you wanted to file a copyright lawsuit against Google?" Hurst asked.

"No," said Catz. "We did not buy Sun to file this lawsuit."

Hurst began to explore the early discussions between Sun's then-CEO Jonathan Schwartz and Oracle executives. Schwartz had been on the witness stand testifying for Google last week, testifying that he had simply failed to do a deal with the company even though he really wanted to.

Catz had a different take on Schwartz's efforts.

"He told us that they’d been talking with Google and had been trying to get them to license Java," Catz said. "And that Android was an unauthorized fork of Java."

"Did Mr. Schwartz ever say to you, in words or otherwise, that Google’s use of the Java platform was OK with Sun?"

"No," said Catz.

With that, time was up for the day, as testimony had reached the 1:00pm deadline set by US District Judge William Alsup. Catz will return to the stand tomorrow morning.