Just reading through the great K&B-book and not encountered any problems so far . But I was a bit surprised about the mentioning of "walloon" in the book. I'm from Belgium (Flanders, the nordern part) and it's a very small country between France, Germany and the Netherlands. So not expected to see something like "walloon" in such an international book.
So just out of curiosity: Kathy and/or Bert, why was "walloon" chosen in the part about java.util.Locale? Did one of you worked in Belgium for several months or years? Or did you just run across the list with language codes and thought "that one sounds funny, let's take that one"?
As always you and your team achieved to create another great book, although I noticed some minor issues: like mixing up "Java 5" and "Java 6" (but maybe all these issues were already mentioned in the errata listing, because I didn't had time to take a look at it). But anyway I was able to pass the exam with an almost perfect score and the question I missed was not mentioned in the book. But certainly won't blame you (or Kathy), but blame Sun for putting such a ridiculous question in the questions database.
And to be 100% correct: the place (and it is more an area) is called Wallonia, the language is Walloon (related to French). The other part is Flanders, with Flemish/Dutch as language. And then there is another very small area where language is German. So a very small country like Belgium (with just 10 millions of people) has 3 different (and official) languages. And this diversity gives a lot of (political) issues and problems.