Sams Teach Yourself J2EE in 21 Days, Second Edition presents the entire enterprise Java architecture in modular, easy-to-comprehend lessons that make it far easier to master this large and complex specification. Each lesson shows exactly how key J2EE tools address specific challenges of N-Tier development. Using the J2EE architecture as a roadmap, the authors describe Enterprise JavaBeans (EJB), JavaServer Pages (JSP), Java Servlets, JMS, JavaMail, JNDI, and much more. Coverage also includes: the role of XML, custom JSP tags, creating J2EE Web Services, and using Java Connectors to interact with legacy and non-Java systems. Along the way, every concept is illustrated with practical, real-world examples to ensure understanding by Java students with diverse levels of experience. The book finishes with sample applications which bring all the pieces together, and give students a comprehensive "forest-and-trees" understanding of J2EE development. These sample applications include a full-fledged Web service.