This book is about Enterprise JavaBeans 1.1 and 2.0 the second and third versions of the Enterprise JavaBeans specification. Just as the Java platform has revolutionized the way we think about software development, Enterprise JavaBeans has revolutionized the way we think about developing mission-critical enterprise software. It combines server-side components with distributed object technologies and asynchronous messaging to greatly simplify the task of application development. It automatically takes into account many of the requirements of business systems: security, resource pooling, persistence, concurrency, and transactional integrity. This book shows you how to use Enterprise JavaBeans to develop scalable, portable business systems. But before we can start talking about EJB itself, we’ll need a brief introduction to the technologies addressed by EJB, such as component models, distributed objects, component transaction monitors (CTMs), and asynchronous messaging. It’s particularly important to have a basic understanding of component transaction monitors, the technology that lies beneath EJB. In Chapters 2 and 3, we’ll start looking at EJB itself and see how enterprise beans are put together. The rest of this book is devoted to developing enterprise beans for an imaginary business and dis cussing advanced issues. It is assumed that you’re already familiar with Java; if you’re not, Exploring Java™ by Patrick Niemeyer and Josh Peck is an excellent introduction. This book also assumes that you’re conversant in the JDBC API, or at least SQL. If you’re not familiar with JDBC, see Database Programming with JDBC™ and Java™, 2nd Edition, by George Reese.