Oracle has accused Google of copying Java API designs into the APIs of its Android mobile operating system; basing Android class libraries on Java API designs; and copying from Java code into Android code.
It also alleges that Google violated its patents - seven were originally cited, but five were overturned before the trial, and only two are being considered.
According to the legal blog Groklaw, the jurors had two questions to ask of the judge during the day, the first being whether Android's method of initialising an array differed from the method set out in US Patent 6,061,520 (for a method and system for performing static initialisation), one of the two patents in question.
The judge asked the lawyers from either side whether they wanted to argue the point in front of the jurors; when they declined in favour of him providing instructions to the jury, Justice Alsup told the jurors that he could offer no guidance as this was a question that went to the heart of the trial and therefore they had to decide it themselves.
He said that if they were to ask a question specific to one of his instructions, he would usually try to answer it. However the question they had raised was asking if one could take a particular fact as evidence that Android's array initialisation diverges from the patented method.
Justice Alsup said he had previously told the jury what was evidence in this case, and what was not and was not about to repeat himself.
He said the question that the jurors had asked was one that went to the weight of the evidence and how to evaluate it; that was for the jury to decide, and it was not for the court to give them further guidance at this point.
The jury later came in with a request that a portion of the testimony by Stanford University professor John Mitchell, who was an expert witness for Oracle, be read to them. The portion they referred to was about pattern matching versus simulated execution.
The question concerns the same patent as the first question; Google's lawyer Robert Van Nest, in his closing arguments, had pointed out that all expert witnesses had agreed that for violation of this patent to be upheld, every single method it claimed had to be used. He added that Android did not use simulated execution, but rather pattern matching.
While the members of the jury have not exhibited any signs of technical nous, the judge sprang a surprise earlier in the week by revealing that he was able to code in a number of languages and had been learning bits of Java recently.
Justice Alsup made the disclosure at an unfortunate juncture for Oracle's high-profile lawyer David Boies, as the latter, just prior to this, had been trying to argue that the use of nine lines of code from Java's rangeCheck function would make a big difference to the speed at which Android functioned and that these lines of code were in some way unique.
When Justice Alsup pointed out that he had several times written code similar to rangeCheck and that it would be far easier for someone to write such code than to steal it, Boies was suitably deflated.