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<concept id="cjavaee5" xml:lang="en-us"> | |
<title outputclass="id_title"><tm tmclass="special" tmowner="Sun Microsystems, Inc." | |
tmtype="tm" trademark="Java">Java</tm> EE 5: Overview</title> | |
<shortdesc outputclass="id_shortdesc">Using the <tm tmclass="special" tmowner="Sun Microsystems, Inc." | |
tmtype="tm" trademark="Java">Java</tm> Platform, Enterprise Edition (<tm tmclass="special" | |
tmowner="Sun Microsystems, Inc." tmtype="tm" trademark="Java">Java</tm> EE) | |
architecture, you can build distributed Web and enterprise applications. This | |
architecture helps you focus on presentation and application issues, rather | |
than on systems issues.</shortdesc> | |
<prolog><metadata> | |
<keywords><indexterm>Java EE 5</indexterm><indexterm>Oerview</indexterm></keywords> | |
</metadata></prolog> | |
<conbody> | |
<p>You can use the <tm tmclass="special" tmowner="Sun Microsystems, Inc." | |
tmtype="tm" trademark="Java">Java</tm> EE 5 tools and features to create applications | |
that are structured around modules with different purposes, such as Web sites | |
and Enterprise <tm tmclass="special" tmowner="Sun Microsystems, Inc." tmtype="tm" | |
trademark="JavaBeans">JavaBeans</tm> (EJB) applications. When you use EJB | |
3.0 components, you can create a distributed, secure application with transactional | |
support. When you develop applications that access persistent data, you can | |
use the new <tm tmclass="special" tmowner="Sun Microsystems, Inc." tmtype="tm" | |
trademark="Java">Java</tm> Persistence API (JPA). This standard simplifies | |
the creation and use of persistent entities, as well as adding new features. | |
For developing presentation logic, you can use technologies such as JavaServer | |
Pages (JSP) or JavaServer Faces (JSF).</p> | |
<p>Using the <tm tmclass="special" tmowner="Sun Microsystems, Inc." tmtype="tm" | |
trademark="Java">Java</tm> EE 5 Platform Enterprise Edition (Java EE) , you | |
can develop applications more quickly and conveniently than in previous versions. | |
The <tm tmclass="special" tmowner="Sun Microsystems, Inc." tmtype="tm" trademark="Java">Java</tm> EE | |
5 platform replaces <tm tmclass="special" tmowner="Sun Microsystems, Inc." | |
tmtype="tm" trademark="Java">Java</tm> 2 Enterprise Edition (J2EE), version | |
1.4. The product tools support for both versions. Java EE 5 significantly | |
enhances ease of use providing<ul> | |
<li>Reduced development time</li> | |
<li>Reduced application complexity</li> | |
<li>Improved application performance</li> | |
</ul></p> | |
<p>Java EE 5 provides a simplified programming model, including the following | |
tools:<ul> | |
<li>Inline configuration with annotations, making deployment descriptors now | |
optional</li> | |
<li>Dependency injection, hiding resource creation and lookup from application | |
code</li> | |
<li>Java persistence API (JPA) allows data management without explicit SQL | |
or JDBC</li> | |
<li>Use of plain old Java objects (POJOs) for Enterprise JavaBeans and Web | |
services</li> | |
</ul></p> | |
<p>Java EE 5 provides simplified packaging rules for enterprise applications:<ul> | |
<li>Web applications us .WAR files</li> | |
<li>Resource adapters use .RAR files</li> | |
<li>Enterprise applications use .EAR files</li> | |
<li>The <codeph>lib</codeph> directory contains shared .JAR files</li> | |
<li>A .JAR file with <codeph>Main-Class</codeph> implies an application client</li> | |
<li>A .JAR file with @Stateless annotation implies an EJB application</li> | |
<li>Many simple applications no longer require deployment descriptors, including<ul> | |
<li>EJB applications (.JAR files)</li> | |
<li>Web applications that use JSP technology only</li> | |
<li>Application clients</li> | |
<li>Enterprise applications (.EAR files)</li> | |
</ul></li> | |
</ul></p> | |
<p>Java EE 5 provides simplified resource access using dependency injection:<ul> | |
<li>In the Dependency Injection pattern, an external entity automatically | |
supplies an object's dependencies.<ul> | |
<li>The object need not request these resources explicitly</li> | |
</ul></li> | |
<li>In Java EE 5, dependency injection can be applied to all resources that | |
a component needs<ul> | |
<li>Creation and lookup of resources are hidden from application code</li> | |
</ul></li> | |
<li>Dependency injection can be applied throughout Java EE 5 technology:<ul> | |
<li>EJB containers</li> | |
<li>Web containers</li> | |
<li>Clients</li> | |
<li>Web services</li> | |
</ul></li> | |
</ul></p> | |
</conbody> | |
</concept> |