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<title outputclass="id_title">J2EE architecture</title>
<shortdesc outputclass="id_shortdesc">The <tm tmclass="special" tmowner="Sun Microsystems, Inc."
tmtype="tm" trademark="Java">Java</tm> 2 Platform, Enterprise Edition (J2EE)
provides a standard for developing multitier, enterprise services.</shortdesc>
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<keywords><indexterm>J2EE development<indexterm>architecture</indexterm></indexterm>
</keywords>
</metadata></prolog>
<conbody outputclass="id_conbody">
<p outputclass="anchor_topictop">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.</p>
<p>J2EE architecture supports component-based development of multi-tier enterprise
applications. A J2EE application system typically includes the following tiers:</p>
<ul>
<li><b>Client tier</b>: In the client tier, Web components, such as Servlets
and JavaServer Pages (JSPs), or standalone <tm tmclass="special" tmowner="Sun Microsystems, Inc."
tmtype="tm" trademark="Java">Java</tm> applications provide a dynamic interface
to the middle tier.</li>
<li><b>Middle tier</b>: 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.</li>
<li><b>Enterprise data tier</b>: In the data tier, the enterprise's data is
stored and persisted, typically in a relational database.</li>
</ul>
<p>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.</p>
<p>For more information on J2EE architecture and its implicit technologies,
download and read the <xref format="html" href="http://java.sun.com/j2ee/download.html#platformspec"
scope="external">J2EE 1.4 Specification<desc></desc></xref>.</p>
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