Introduction; About This Guide; Enterprise Javabeans; What Does What - Red Hat APPLICATION SERVER - JONAS Tutorial

This tutorial explains how to configure and run the Red Hat Application Server server. In addition,
it explains how to run the examples provided in the Red Hat Application Server distribution. It is
assumed that a JDK is already installed. For installation details, refer to the Red Hat Application
Server Installation Guide.

1.1. About this Guide

This introduction gives an overview of Red Hat Application Server. For those who want to imme-
diately start using Red Hat Application Server without going through the overview, you can go to
Chapter 2 Quick Start.
Chapter 3 Configuring Your Environment helps you set up all the software needed for a complete J2EE
environment, including a Web server, Servlet, and EJB (Enterprise JavaBean) servers.
Chapter 4 Getting Started With JOnAS is a quick reference to JOnAS that guides you through the most
common tasks you will have to perform.
The remaining chapters are specific to EJB application development. Each chapter treats a different
programming concept and illustrates it with a specific example. The Alarm application is a "putting
it all together" example that gives an overview of a complete application using JOnAS.

1.2. Enterprise JavaBeans

The Sun Enterprise JavaBeans specification (http://java.sun.com/products/ejb/docs.html) defines an
architecture and interfaces for developing and deploying distributed Java server applications based on
a multi-tier architecture.
The intent of this specification is to facilitate and normalize the development, deployment, and as-
sembly of application components (called enterprise beans); such components will be deployable on
EJB platforms. The resulting applications are typically transactional, database-oriented, multi-user,
secured, scalable, and portable. More precisely, this EJB specification addresses the following areas:
The runtime environment, called the EJB server, which provides the execution environment together
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with the transactional service, the distribution mechanisms, the persistence management, and the
security.
A programmer and user guide explaining how an enterprise bean should be developed, deployed,
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and used.
Not only will an enterprise bean be independent of the platform and operating system (since it is
written in Java), but also of the EJB platform.

1.2.1. What Does What?

The Java2 Enterprise Edition (J2EE) platform is an n-tier platform. Each tier has a specific role:
Clients. Clients are the end-users of the system and can access the J2EE server by several means.
One of the most common is to use a Web browser such as Mozilla to connect to a Web server where
Java Servlets or Java Server Pages (JSP) access the business logic of the J2EE server (see Figure 1-1).
Another solution is to use a specific Java program that directly communicates with the J2EE server
(see Figure 1-2).
Chapter 1.

Introduction