The Enterprise JavaBeans architecture is a component architecture for the development and deployment of component-based distributed business applications. Applications written using the Enterprise JavaBeans architecture are scalable, transactional, and multi-user secure. These applications may be written once, and then deployed on any server platform that supports the Enterprise JavaBeans specification.
That’s a mouthful, but it’s not atypical of how Sun defines many of its Java technologies—have you ever read the definition of the Java language itself? It’s about twice as long. This book offers a shorter definition of EJB:
Enterprise JavaBeans is a standard server-side component model for component transaction monitors.
We have already set the stage for this definition by briefly defining the terms “distributed objects,” “server-side components,” and “component transaction monitors.” To provide you with a complete and solid foundation for learning about Enterprise JavaBeans, this chapter will now expand on these definitions.
If you already have a clear understanding of distributed objects, transaction monitors, CTMs, and asynchronous messaging, feel free to skip the rest of this chapter and move on to Chapter 2.
 Sun Microsystems’ Enterprise JavaBeans™ Specification, v2.0, Copyright 2001 by Sun Microsystems, Inc.