From the reviews:
"An introduction to the new Java Persistence application programming interfaces (APIs), this book serves not only as a tutorial on how to use them, but also as a basic reference text. … The book is very well written, and the technical material is presented clearly without excessive detail. … this is an excellent textbook." (M. S. Joy, ACM Computing Reviews, Vol. 49 (3), March, 2008)
EJB 3.0 sets a new precedent. It has made huge advances in ease of development, and its drastically simplified programming model has been widely acclaimed. This book is the definitive guide to EJB 3.0 persistence technology. The authors provide unparalleled insight and expertise on this topic, fully examining and explaining EJB 3.0 persistence specification. They describe how to use this sophisticated technology to its full potential, including The new EntityManager API The new features of EJB Query Language (EJB QL) Basic and advanced object-relational mapping Advanced topics like concurrency, locking, inheritance, and polymorphism Assuming a basic knowledge of Java, SQL, JDBC, and some J2EE experience, this book teaches you EJB 3 persistence from the ground up. After reading it, you will have an in-depth understanding of the EJB 3.0 Persistence API and how to use it in your applications.