On Demand Applications – Enterprise Java Bean Application Development With a Three-Tier Architecture
Enterprise java beans is basically a server side component architecture for developing modular enterprise applications based on the java platform.EJB basically encapsulates the business logic and implements back end business logic of an enterprise application.
Any mention of enterprise java bean application development would be incomplete without gaining an understanding of what a java session bean actually is. Java session beans are actually java components that run in either stand -alone EJB containers or EJB containers that are part of the standard java platform enterprise edition application servers. These java beans are typically used to model a particular task or use case such as input of customer information or executing a process that maintains a conversation state with a client application.
Most database driven applications that are developed using open source technologies have a three-tier structure. The web application itself runs in the browser of a desktop or a laptop. Users can only access the front end of the application to input data or search strings. Java being platform independent allows applications to be accessed on any device like a pda or cellphone or any telnet device.
Enterprise java bean application development occurs by employing a three-tier architecture consisting of a front end known as the web container, an EJB container, the third tier being the database. This three-tier structure has proved to be immensely useful for enterprise application development.
The application when accessed on any telnet device renders a user interface complete with data entry screens and submit buttons on to the user’s device. This interface is usually developed by using any of the technologies such as java server pages, java server faces, or java servlets. Any event fired by the user like a search string or a request to add certain items into a shopping cart invokes a call session bean running in an Enterprise java bean container. Any of the above-mentioned technologies JSP,JSF, java servlets can be used to call a session bean. Since the Enterprise java bean container is connected to the database, it has the capability to process the queries of the users. Once the session bean is invoked , it processes the request and sends a response back to the web application. The web application then formats the response as required and returns a response to the client end.
Being open source EJB application development has a very bright future in the enterprise application development space in the times to come.