Hibernate practically exploded onto the Java scene. Why? Because with it developers avoid a dreaded problem: object/relational mapping (ORM). There's a mismatch between your object-oriented code and the relational database you use. This object/relational mismatch requires you to write persistence code that maps one to the other, code which is often complex, tedious and costly to develop. Hibernate does it for you.
But not only that, Hibernate makes persistence easy. Positioned as a layer between your application and your database, Hibernate takes care of loading and saving of objects. Hibernate apps are cheaper, more portable, and more resilient to change. And they perform better than anything you are likely to develop yourself.
Hibernate in Action carefully explains the concepts you need, then gets you started quickly. Using a single, continuing example, it shows you how to use Hibernate in practice, how to deal with concurrency and transactions, how to efficiently retrieve objects and use caching. The authors developed Hibernate. They answered many community questions. Their experience seeps out of every pore of this book.