We had three goals when writing this book, so you can read it as
Usually, books are either tutorials or reference guides, so this stretch comes at a price. If you're new to Hibernate, we suggest that you start reading the book from the start, with the tutorials in chapters 1 and 2. If you have used an older version of Hibernate, you should read the first two chapters quickly to get an overview and then jump into the middle with chapter 3.
We will, whenever appropriate, tell you if a particular section or subject is optional or reference material that you can safely skip during your first read.
This book is divided into three major parts.
In part 1, we introduce the object/relational paradigm mismatch and explain the fundamentals behind object/relational mapping. We walk through a hands-on tutorial to get you started with your first Hibernate, Java Persistence, or EJB 3.0 project. We look at Java application design for domain models and at the options for creating object/relational mapping metadata.
Mapping Java classes and properties to SQL tables and columns is the focus of part 2. We explore all basic and advanced mapping options in Hibernate and Java Persistence, with XML mapping files and Java annotations. We show you how to deal with inheritance, collections, and complex class associations. Finally, we discuss integration with legacy database schemas and some mapping strategies that are especially tricky.
Part 3 is all about the processing of objects and how you can load and store data with Hibernate and Java Persistence. We introduce the programming interfaces, how to write transactional and conversation-aware applications, and how to write queries. Later, we focus on the correct design and implementation of layered Java applications. We discuss the most common design patterns that are used with Hibernate, such as the Data Access Object (DAO) and EJB Command patterns. You'll see how you can test your Hibernate application easily and what other best practices are relevant if you work an object/relational mapping software.
Finally, we introduce the JBoss Seam framework, which takes many Hibernate concepts to the next level and enables you to create conversational web applications with ease. We promise you'll find this chapter interesting, even if you don't plan to use Seam.
Readers of this book should have basic knowledge of object-oriented software development and should have used this knowledge in practice. To understand the application examples, you should be familiar with the Java programming language and the Unified Modeling Language.
Our primary target audience consists of Java developers who work with SQL-based database systems. We'll show you how to substantially increase your productivity by leveraging ORM.
If you're a database developer, the book can be part of your introduction to object-oriented software development.
If you're a database administrator, you'll be interested in how ORM affects performance and how you can tune the performance of the SQL database-management system and persistence layer to achieve performance targets. Because data access is the bottleneck in most Java applications, this book pays close attention to performance issues. Many DBAs are understandably nervous about entrusting performance to tool-generated SQL code; we seek to allay those fears and also to highlight cases where applications shouldn't use tool-managed data access. You may be relieved to discover that we don't claim that ORM is the best solution to every problem.
This book provides copious examples, which include all the Hibernate application artifacts: Java code, Hibernate configuration files, and XML mapping metadata files. Source code in listings or in text is in a fixed-width font like this to separate it from ordinary text. Additionally, Java method names, component parameters, object properties, and XML elements and attributes in text are also presented using fixed-width font.
Java, HTML, and XML can all be verbose. In many cases, the original source code (available online) has been reformatted; we've added line breaks and reworked indentation to accommodate the available page space in the book. In rare cases, even this was not enough, and listings include line-continuation markers. Additionally, comments in the source code have often been removed from the listings when the code is described in the text.
Code annotations accompany some of the source code listings, highlighting important concepts. In some cases, numbered bullets link to explanations that follow the listing.
Hibernate is an open source project released under the Lesser GNU Public License. Directions for downloading Hibernate packages, in source or binary form, are available from the Hibernate web site: www.hibernate.org/.
The source code for all Hello World and CaveatEmptor examples in this book is available from http://caveatemptor.hibernate.org/ under a free (BSD-like) license. The CaveatEmptor example application code is available on this web site in different flavors—for example, with a focus on native Hibernate, on Java Persistence, and on JBoss Seam. You can also download the code for the examples in this book from the publisher's website, www.manning.com/bauer2.
Christian Bauer is a member of the Hibernate developer team. He works as a trainer, consultant, and product manager for Hibernate, EJB 3.0, and JBoss Seam at JBoss, a division of Red Hat. With Gavin King, Christian wrote Hibernate in Action.
Gavin King is the founder of the Hibernate and JBoss Seam projects, and a member of the EJB 3.0 (JSR 220) expert group. He also leads the Web Beans JSR 299, a standardization effort involving Hibernate concepts, JBoss Seam, JSF, and EJB 3.0. Gavin works as a lead developer at JBoss, a division of Red Hat.
Your purchase of Java Persistence with Hibernate includes free access to a private web forum run by Manning Publications, where you can make comments about the book, ask technical questions, and receive help from the authors and from other users. To access the forum and subscribe to it, point your web browser to www.manning.com/bauer2. This page provides information on how to get onto the forum once you are registered, what kind of help is available, and the rules of conduct on the forum.
Manning's commitment to our readers is to provide a venue where a meaningful dialogue among individual readers and between readers and the authors can take place. It is not a commitment to any specific amount of participation on the part of the author, whose contribution to the AO remains voluntary (and unpaid). We suggest you try asking the authors some challenging questions, lest their interest stray!
The Author Online forum and the archives of previous discussions will be accessible from the publisher's website as long as the book is in print.
