THE BASICS OF JAVA EE - Java EE Design Patterns - page 18

THE EIS TIER
The EIS tier consists of data storage units, often in the form of databases, but they can be any
resource that provides data. It may be an antiquated legacy system or a i le system.
NOTE The EIS tier is often referred to as the Data tier, Persistence tier, and
Integration tier.
JAVA EE SERVERS
As you have seen, the Middle tier hosts the Java EE server, which provides the Java EE functionality
needed for an enterprise application.
Java EE is based on 30 standards, called Java Specii cation Requests (JSRs) ( http://www.oracle
.com/technetwork/java/javaee/tech/index.html ). These requests go through the Java
Community Process (JCP) before they can become accepted as part of the Java EE universe. The JCP
is an open process in which anyone can participate and give feedback on JSRs or even submit their
own JSR ( https://www.jcp.org/en/home/index ).
These specii cations are bundled together and represent the technologies that a server application
must implement to be able to claim that it is Java EE compliant.
Additionally, Oracle requires that the server application passes the Technology
Compatibility Kit (TCK). This is a nontrivial test suite that checks that the application
server behaves as the specii cation requires. This ensures that if you develop your application
following the Java EE specii cations, you will be able to deploy and execute it on any Java EE
application.
At the time of writing, three application servers have been certii ed fully compatible with Java
EE 7. They are GlassFish Server Open Source Edition 4.0 ( http://glassfish.java.net ),
Wildl y 8.0.0 ( http://wildfly.org ), an d TMAX JEUS 8 ( http://tmaxsoft.com/product/jeus/
certification/). E leven application servers are Java EE 6 compatible ( http://en.wikipedia
.org/wiki/Java_Platform,_Enterprise_Edition#Java_EE_6_certified ).
THE JAVA EE WEB PROFILE
The Java EE web proi le is a subset of technologies that comprise the most appropriate
technologies required for the development of web‐based enterprise applications. The proi le
reduces the size and complexity of the platform to just the technologies required for the
development of a modern web application. The web proi le is a complete stack comprising
technologies related to workl ow and core functionality (Servlet), presentation (JSF and JSP),
business logic (EJB lite), transactions (JTA), persistence (JPA), the new WebSocket, and much
more. It omits a lot of enterprise‐related technologies such as the Concurrency Utilities, Java