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4.1: Programming model and environment

4.1: Programming model and environment

IBM WebSphere Application Server supports a three-tier programming model in which the application server and its contents -- your applications -- reside in the middle tier.

In this multi-tiered programming model, tier 0 represents Applets which run in a Web browser; tier 1, some application resources such as JSP files and servlets, which respond to HTTP requests; tier 2, the enterprise beans that run on the EJB server; and tier 3, the databases that store the business data. With version 4.0, WebSphere Application Server provides tier 0 support by shipping a "thin" remote client. See article Java clients for more information.

This documentation is geared towards the following layered approach to application development:

  1. Determine what the application should do
  2. Plan the application building blocks and their interactions
  3. Create the Web application building blocks
  4. Write the Web application deployment descriptor
  5. Combine the Web application components and deployment descriptor into a Web module
  6. Create the enterprise beans
  7. Write the EJB deployment descriptor
  8. Combine the enterprise beans and the deployment descriptor into an EJB module
  9. Package the Web module and EJB module into a J2EE application.

A Web developer working in the J2EE environment is therefore responsible for the following tasks:

  • Writing, compiling, and testing the source code
  • Writing the JSP and HTML files
  • Specifying the deployment descriptor
  • Bundling the servlet.class, .jsp, .html and deployment descriptor files into a Web application archive or WAR file
  • Bundling the ejb.class and deployment descriptor file into a JAR file
  • Assembling the EJB JAR and WAR files into a J2EE application enterprise archive resource or EAR file
Go to previous article: Developing applications Go to next article: Finding supported specifications

 

 
Go to previous article: Developing applications Go to next article: Finding supported specifications