Mark Watson published a new book, Practical Artificial Intelligence Programming in Java, 3rd edition. You can buy it in print, or download a PDF version for free, with the code.
Chapters 8 (Machine Learning with WEKA), 9 (Statistical NLP), and 10 (Information Gathering) are all highly relevant for those of us in IR/text processing fields.
The code is designed to be easy to learn and to teach concepts rather than being the most efficient, or latest state-of-the-art. One good benefit is that recommends other implementations for those seeking more depth.