OSGi In Practice

I've just started reading OSGi In Practice, by Neil Bartlett. Despite the title, it's not part of the Manning Press series, but instead is free and under a Creative Commons license. Despite the author's claim that it's a working draft, it's better written than a lot of published technical books.

I'm just to Chapter 2, but so far, it's a great introduction. He's given a terrific history of the need for a complete module system in Java, the pitfalls of the hierarchical classloader world and first-found-first used classloading. I'm really excited about this book. I recommend checking it out.