Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
If you want to create a free software content management server fast and starting with zero knowledge, and then vigorously and systematically play with a Java based web application, then the book Managing and Customizing OpenCMS 6 by Matt Butcher is the accurate, project orientated and a pragmatic book that you are looking for.
The author has written this book in a systematic and rigorous project orientated manner. What I mean to say by this is that, if I knew nothing of the product and wished to implement it quickly, I would be asking the questions answered in the book. Personally, as I worked my way through my own little project, I found that the book’s 240 pages were exactly the right number of pages required to achieve my objectives, not one page too much or too few.