"The Java language is not useful without the ability to make something happen, and what the API does is allow you to make something happen," Schmidt told the jury.
Oracle says the APIs are complex creative works, like the blueprints for a house.
"Did anyone at Sun call the APIs 'blueprints?'" Google's lawyer asked Schmidt.
Schmidt said they did not.
Earlier in the day, Oracle finished its questioning of Andy Rubin, the head of Google's Android division. Boies wanted Rubin to admit that Google knew Sun was concerned about the fragmentation of Java.
The answer could affect any damages awarded to Oracle, and Rubin seemed determined not to give Boies the answer he wanted. He said several times that he didn't know how Sun defined "fragmentation."
The normally calm and measured Boies grew exasperated, at one point raising his voice.
"Did you ever ask what people meant when they talked about fragmentation?" Boies asked.
"No," said Rubin.
"The reason you didn't ask is because you knew perfectly well what fragmentation meant, didn't you sir?" Boies said pointedly.
The trial is divided into three phases, to address copyrights, patents and damages. Oracle is seeking about US$1 billion in damages, as well as an injunction that could force Google to change the way it built Android.
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