TUTORIAL ON THE ENTERPRISE JAVABEANS (EJB)
COMPONENT MODEL

Yi Liu
Department of Computer and Information Science
University of Mississippi
University, MS 38677 USA
liuyi@cs.olemiss.edu

 

        Enterprise JavaBeans (EJB) is a software component model for developing and deploying enterprise-level, server-side computing applications that are scalable, transactional, and multi-user secure [1]. The model simplifies the development of middleware by providing server support for services such as transactions, security, database connectivity, and component customization [2]. It is a currently important technology in component-based system implementation.

        This tutorial demonstrates the Enterprise JavaBeans model and how to build server-side Java components using the Java 2 Enterprise Edition (J2EE) platform. The tutorial presentation will be organized in three parts.

        The first part is an introduction to the basic concepts of the EJB component model. To know the EJB technology, one must understand what EJB is and what it can do. In this part, the following questions are discussed: What is an Enterprise JavaBean? What is the EJB container? What is the structure of an Enterprise JavaBean? EJB is a component technology. So, basic concepts and basic architecture of components will be briefly introduced.

        The second part brings the introduction of three EJB component types: entity beans, session beans, and message-driven beans. This is the most important part of the tutorial. It focuses on the basic structure of each bean type, how these types are distinct from each other, how to code them, and in what circumstances each type can be used. This part uses a “course registration system” case study which was designed and coded by the presenter and her colleagues using component specification methods.

        The third part demonstrates how to use the J2EE deploytool to install EJBs and shows how EJBs and JavaServer Pages (JSP) can work together. Firstly, the presenter demonstrates how to install J2EE and how to deploy EJBs and JavaServer Pages. Secondly, the presenter shows how to debug problems that are encountered frequently during deployment and execution of Enterprise JavaBeans.

        This tutorial should be helpful to those who are interested in component technologies but who have had no chance to exploit them. The presenter wants to help them take the first step of their exploration.

REFERENCES
[1] D. Blevins. “Overview of the Enterprise JavaBeans Component Model,” In G.T. Heineman and W. T. Councill (editors), Component-based Software Engineering: Putting the pieces Together, Addison Wesley, 2001.
[2] Sun Microsystems. Java 2 Enterprise Edition Platform White Papers, <http://java.sun.com/j2ee/white/index.html> , accessed 7 December 2002.