background image

Java EE Components

<< Enterprise information system (EIS) | Application Clients >>
<< Enterprise information system (EIS) | Application Clients >>

Java EE Components

standard login mechanisms so application developers do not have to implement these
mechanisms in their applications. The same application works in a variety of different security
environments without changing the source code.
Java EE Components
Java EE applications are made up of components. A Java EE component is a self-contained
functional software unit that is assembled into a Java EE application with its related classes and
files and that communicates with other components.
The Java EE specification defines the following Java EE components:
Application clients and applets are components that run on the client.
Java Servlet, JavaServer Faces, and JavaServer Pages
TM
(JSP
TM
) technology components are
web components that run on the server.
Enterprise JavaBeans
TM
(EJB
TM
) components (enterprise beans) are business components
that run on the server.
Java EE components are written in the Java programming language and are compiled in the
same way as any program in the language. The difference between Java EE components and
"standard" Java classes is that Java EE components are assembled into a Java EE application, are
verified to be well formed and in compliance with the Java EE specification, and are deployed to
production, where they are run and managed by the Java EE server.
Java EE Clients
A Java EE client can be a web client or an application client.
Web Clients
A web client consists of two parts: (1) dynamic web pages containing various types of markup
language (HTML, XML, and so on), which are generated by web components running in the
web tier, and (2) a web browser, which renders the pages received from the server.
A web client is sometimes called a thin client. Thin clients usually do not query databases,
execute complex business rules, or connect to legacy applications. When you use a thin client,
such heavyweight operations are off-loaded to enterprise beans executing on the Java EE server,
where they can leverage the security, speed, services, and reliability of Java EE server-side
technologies.
Distributed Multitiered Applications
The Java EE 5 Tutorial · September 2007
44