The trial is being held in three phases. This first, which could wrap up by Friday, is to determine the copyright accusations. The second is for the patent accusations, and the third will decide what damages Oracle will be awarded if it prevails on either of the first two.

That was the original plan anyway, although the judge in the case, William Alsup, indicated Monday that he might ask the jury to decide any copyright damages at the end of this first phase. That's because any damages will depend partly on whether Google's copyright infringement was wilful, and the judge has said Rubin's emails might be evidence of wilful infringement.

He thinks it might be better, therefore, for the jurors to decide damages while the emails are fresh in their minds. He didn't make a decision on that Monday but asked the lawyers for both sides to think about it.

A bigger question in the case is whether most of the code that Google is accused of copying can be protected by copyright at all. That's something the judge will rule on himself, based on the evidence in the case and his interpretation of the law.

The most serious copyright claim against Google involves 37 Java APIs, or application programming interfaces, that Google is said to have copied from Java for use in Android.