The Java™ 2 Platform, Enterprise Edition (J2EE)
provides a standard for developing multitier, enterprise applications.
The economy and technology of today have intensified the need for faster,
more efficient, and larger-scale information management solutions. The J2EE
specification satisfies these challenges by providing a programming model
that improves development productivity, standardizes the platform for hosting
enterprise applications, and ensures portability of developed applications
with an extensive test suite.
J2EE architecture supports component-based development of multi-tier enterprise
applications. A J2EE application system typically includes the following tiers:
- Client tier
- In the client tier, Web components, such as Servlets and JavaServer Pages
(JSPs), or standalone Java applications provide a dynamic interface
to the middle tier.
- Middle tier
- In the server tier, or middle tier, enterprise beans and Web Services
encapsulate reusable, distributable business logic for the application. These
server-tier components are contained on a J2EE Application Server, which provides
the platform for these components to perform actions and store data.
- Enterprise data tier
- In the data tier, the enterprise's data is stored and persisted, typically
in a relational database.
J2EE applications are comprised of components, containers, and services.
Components are application-level components. Web components, such as Servlets
and JSPs, provide dynamic responses to requests from a Web page. EJB components
contain server-side business logic for enterprise applications. Web and EJB
component containers host services that support Web and EJB modules.
For more information on J2EE architecture and its implicit technologies,
download and read the
J2EE 1.4 Specification.