As mentioned earlier, JavaEE is an Enterprise Edition of Java which can be used for creating web applications for supporting big & medium enterprises. In today’s demanding world, companies are looking for cost, time & resource efficient approaches to application development.
In order to reduce cost of development and fast track the development of an application for any Enterprise, JavaEE provides a component approach to design, develop and deploy the application. The main advantage of this component approach is re-usability of those components & they are distributed. Distributed means the logic of the application or business is divided across different components and they work on different machine.
Moreover, JavaEE Components define a set of standards and there are several vendors providing the different implementations for the same components.
Components of JavaEE
JavaEE applications are mostly three tiered, as the application is distributed across three different locations.
A JavaEE client can be a web-based client or a desktop based client. Web-based clients includes web-pages which directly rely on the data retrieved from the components in the Business Tier. They do not query database, but just interact the components on the Business Tier. They are also referred to as thin clients sometimes. Thin client connects to any JavaEE application and provides services, it can connect to anyones’ application hosted anywhere. On the other hand, thick clients are standalone application which can run on its’ own, and it communicates with the server less frequently as compared to thin clients. Client Components includes Web Pages, Standalone Java Application, Mobile Application which are connecting to any JavaEE web application running in some area of a network.
Business tier forms the part of application where the business logic relies, and this is where the all the business rules are implemented for the domain of your application. It also includes the Web-Tier Components where a Servlet or Java Beans Components provide some basis of data for the clients to execute, and show data. It also connects to the databases to get data for providing necessary domain services based on the requests from the clients. Business-tier components comprises of Java Servlets, Enterprise Beans, JSF etc.
Enterprise Information System
This is the place from where the JavaEE application will usually get the data is needs to performs its’ business in the Business tier. It can connect to another ERP Systems, or EIS Systems to get data, or conect to any database for getting the data to be provided to the Business Tier for performing its’ functions.