Developers today increasingly recognize the need for distributed, transactional, and portable applications that
leverage the speed, security, and reliability of server-side technology. In the world of
information technology, enterprise applications must be designed, built, and produced for less money,
with greater speed, and with fewer resources.
With the JavaTM Platform, Enterprise Edition (Java EE), development of Java enterprise applications
has never been easier or faster. The aim of the Java EE 5
platform is to provide developers a powerful set of APIs while reducing development
time, reducing application complexity, and improving application performance.
The Java EE 5 platform introduces a simplified programming model. With Java EE
5 technology, XML deployment descriptors are now optional. Instead, a developer can simply
enter the information as an annotation directly into a Java source file, and
the Java EE server will configure the component at deployment and runtime. These
annotations are generally used to embed in a program data that would otherwise
be furnished in a deployment descriptor. With annotations, the specification information is put
directly in your code next to the program element that it affects.
In the Java EE platform, dependency injection can be applied to all resources
that a component needs, effectively hiding the creation and lookup of resources from
application code. Dependency injection can be used in EJB containers, web containers, and
application clients. Dependency injection allows the Java EE container to automatically insert references
to other required components or resources using annotations.
The Java Persistence API is new to the Java EE 5 platform. The
Java Persistence API provides an object/relational mapping for managing relational data in enterprise
beans, web components, and application clients. It can also be used in Java
SE applications, outside of the Java EE environment.
This tutorial uses examples to describe the features and functionalities available in the
Java EE 5 platform for developing enterprise applications. Whether you are a new
or experienced Enterprise developer, you should find the examples and accompanying text a
valuable and accessible knowledge base for creating your own solutions.
If you are new to Java EE enterprise application development, this chapter is
a good place to start. Here you will review development basics, learn
about the Java EE architecture and APIs, become acquainted with important terms and concepts,
and find out how to approach Java EE application programming, assembly, and deployment.