Programming Tutorials

Distributed Multi-tiered Applications

By: aathishankaran Printer Friendly Format    

Distributed Multi-tiered Applications

The J2EE platform uses a multi-tiered distributed application model. Application logic is divided into components according to function, and the various application components that make up a J2EE application are installed on different machines depending on the tier in the multi-tiered J2EE environment to which the application component belongs. Figure shows two multi-tiered J2EE applications divided into the tiers described in the following list. The J2EE application parts shown are presented in J2EE Components.

·         Client-tier components run on the client machine.

·         Web-tier components run on the J2EE server.

·         Business-tier components run on the J2EE server.

·         Enterprise information system (EIS)-tier software runs on the EIS server.

 

Although a J2EE application can consist of the three or four tiers shown in Figure, J2EE multi-tiered applications are generally considered to be three-tiered applications because they are distributed over three different locations: client machines, the J2EE server machine, and the database or legacy machines at the back end.

 

Three-tiered applications that run in this way extend the standard two-tiered client and server model by placing a multithreaded application server between the client application and back-end storage.