You have to know that I’ve tried. Honestly, I did. I hoped to be able to read each and every page of “Java persistence with Hibernate” (revised edition of “Hibernate in action”), by Christian Bauer and Gavin King. But, I gave up before reading a third of it, then I continued only reading some sections. First, because I know Hibernate, I’ve used Hibernate in all the Java projects I’ve been involved with – in the last 5 years or so. Second, because the content from the first edition is more than familiar to me. And third, because this second edition is a massive > 800 pages book (double the number of pages in the first edition). At that rate, the fourth edition will be sold together with some sort of transportation device, because a mere human will not be able to carry that amount of paper. How did this happened ?Hibernate is the perfect example of a successful Java open-source project. Initially started as a free alternative to commercial object-relational mapping tools, it quickly became mainstream. Lots of Java developers around the world use Hibernate for the data layer inside their projects. It’s very comfortable, just set some attributes or ask for a business object instance and Hibernate does all the ugly SQL for you. As a developer, you are then comfortably protected from that nasty relational database, and gently swim in a sea of nicely bound objects. Right ? No, not exactly. Each object-relationship mapping tool has its own ways of being handled efficiently, and this is where books like “Java persistence with Hibernate” come into play. This book teaches you how to work with Hibernate, with a “real-world” example: the Caveat-Emptor online auction application. Since the first edition of the book was written, lots of things happened in the Hibernate world and you can see their impact in “Java persistence with Hibernate”. Most important is the release of the 3.x version line and its different ameliorations and new features: code annotations used as mapping descriptors, package naming reorganization inside the API, but most important the standardization under the umbrella of JPA (Java Persistence API) for a smooth integration with EJB 3 inside Java EE 5 servers. And this, is a little bit funny. Yesterday, Hibernate was the main proof that it is possible to make industrial-quality projects within a “J2EE-less” environment, today Hibernate has put a suit and a tie, joined the ranks of Jboss, then Redhat, and it lures the unsuspecting Java developers towards the wonderful and (sometimes) expensive world of Java EE 5 application servers. Which is not necessarily a bad move for the Hibernate API, but it’s a proof that in order to thrive as an open-source project, you need so much more than the Sourceforge account and some passion … Enough with that, let’s take a look at the book content. Some 75% if it is in fact the content of the first edition, updated and completed. You learn what object-relational mapping is, the advantages, the quirks, the recommended way of developing with Hibernate. For a better understanding, single chapters from the initial book were expanded into 2, sometimes more, chapters. The “unit of work” is now called “a conversation” and you’ve got a whole new chapter (11) about conversations, which is in fact pretty good stuff about session and transaction management. Christian and Gavin done some great writing about concurrency and isolation in the relatively small 10-th chapter – which is a must read even if you’re not interested in Hibernate, but you want to understand once and for all what are these concurrent transaction behaviors everyone is talking about. The entire 13th chapter is dedicated to fetching strategy and caching, which is a must read if you want performance and optimization from your application. There is also a good deal of EJB, JPA and EE 5 – related stuff scattered in multiple chapters. And finally, a solid 50-pages chapter is pimping the JSF (Java Server Faces) compliant web development framework, Jboss Seam. I have only managed to read a few pages of this final chapter, so cannot really comment. Note to self: play a little bit with that Seam thing. To conclude, is this a fun book ? No. Is this a perfect book to convert young open-source fanatics to the wonders of Hibernate API ? Nope. Is this a book to read cover to cover during a weekend ? Not even close. Then, what is this ? First, it’s the best book out there about Hibernate (and there are quite a few on the market right now), maybe even the best book about ORM in Java, in general. It has lots of references to EJB, JPA and EE, it will help you to easily sell a Hibernate project to the management. Even if the final implementation uses Spring … And finally, it’s the best Hibernate reference money can buy. When you have an issue, open the darn index and search, there are 90% chances your problem will be solved. And that’s a nice accomplishment. Don’t get this book because it’s funny, because it’s a nice read, about a new innovative open-source project. Buy it because it helps you grok ORM, write better code, deliver quality projects.