As strange as this may sound, Judges are supposed to use their experience but not their knowledge. Technically speaking, knowing computer programming may present a bias in this case. Taking an extreme example, a Judge shouldn't precede over a murder trial that he or she witnessed. Here, the Judge is basically saying, "I know difficult code. I have written difficult code. And, this sir, is not difficult code." Since, Oracle's argument depends in-part on the value of this code, the Judge has arguably decided that issue, which may come up if Oracle is not happy.
I don't disagree with the Judge, but he is not supposed to be making these kinds of factual findings.