Thanks to everyone who has asked about the downloadable code samples promised in the preface of the book. I'm still working on these and had hoped to have them up by now, but there's been a minor set-back and I'm having to rewrite a few of them, so it'll be a few more days. The final product will be a set of ready-to-run applications exercising every example printed in the book and then some, in both Java and Python. The code will be released under an Apache 2.0 license, and will be available as a downloadable archive and as a browsable Mercurial repository. They will be available to the general public (not just purchasers of the book). Of course, I'll post here when they're available.

Despite my ambitions for PGAE to be the first technical book ever written without any errors in the first edition, a few bugs crept their way in without my notice. So far, most of them appear to be in the printed example code. The downloadable samples will include corrections. I'm compiling a list of errata, and am working with O'Reilly to get the bugs fixed in the online edition. See that page for instructions on how to report any bugs you find.

The most notable errata so far is a misprint in the Java example in Chapter 2 that deals with memcache. An older, incomplete version of the source file is used for the sample than is described by the text. The errata page describes the fix, and the complete corrected example will be in the final set of examples when they are released.

Thanks to diligent readers that have reported errata so far. Keep up the good work!