# J2EE Application Programmer's Guide

## Target Audience and Content

The target audience for this guide is the application component provider, i.e. the person in charge of developing the software components on the server side (the business tier).

The content of this guide is the following:

1. Target Audience and Content
2. Principles

- Enterprise Bean Creation
- Web Components Creation
- J2EE Application Assembler
- Application Deployer and Administrator

## Principles

The J2EE application components supported by JOnAS are Enterprise Beans and Web components. Besides application components construction, we provide guides for application assembly, deployment and administration.

### Enterprise Bean Creation

The person in charge with the development of Enterprise Beans should consult the Enterprise Beans Programmer's Guide in order to learn how to:

1. Write the source code for the beans
2. Specify the deployment descriptor
3. Bundle the compiled classes and the deployment descriptor into an EJB JAR file

We provide guides for developping the three entreprise bean types :

- Session beans
- Entity beans
- Message driven beans

Deployment descriptor specification is presented in the Defining the Deployment Descriptor chapter.

More specific issues related to the transaction behavior, the Enterprise Bean environment or security service, are presented in the corresponding chapters: Transactional Behaviour, Enterprise Bean Environment, Security Management.

Principle and tools for providing EJB JAR files are presented in: EJB Packaging and Deployment and Installation Guide.

### Web Components Creation

Web designers in charge with JSP pages, and software developers providing servlets, are invited to consult the Web Application Programmer's Guide.

The Developing Web Components guide explains how to construct Web components, but also how to access Enterprise Beans from within the Web Components.

Deployment descriptor specification is presented in the Defining the Web Deployment Descriptor chapter.

Web components can be used as Web application components, or as J2EE application components. In both cases, a WAR file will be created, but the containt of this file is different in the two situations. In the first case, the WAR contains the Web components and the Enterprise Beans. In the second case, the WAR does not contain the Enterprise Beans. The EJB JAR file containing the Enterprise Beans is packed together with the WAR file containing the Web components, into an EAR file.
Principle and tools for providing WAR files are presented in: WAR Packaging and Deployment and Installation Guide.

### J2EE Application Assembler

The application assembler, in charge with assembling into a J2EE EAR file the application components already bundled in EJB JAR files and WAR files, will find usefull information in the J2EE Application Assembler's Guide chapter.

### Application Deployer and Administrator

JOnAS provide tools for the deployment and administration of Enterprise Beans (EJB JARs), Web applications (WARs) and J2EE applications (EARs).

The Deployment and Installation Guide covers issues related to application components deployment.

The Administration Guide presents how to manage the JOnAS server and the JOnAS services allowing the deployment of the different kind of application components: EJB Container service, Web Container service and EAR service.