This book takes the reader through the details of the EJB 3.0 architecture, and shows how EJB can be used to develop powerful, standards-based backend business logic. It offers practical insights into the entire EJB architecture, covering all areas of the EJB 3.0 specification, including its new persistence framework, simplified development model, and other key new features. In addition, it covers upgrade headaches: common issues encountered when migrating from EJB 2.1 to EJB 3.0, highly relevant to existing EJB developers. The book is designed to be the first and only comprehensive beginning or introductory EJB 3 book to market.