Datasheet

8
Part I ✦ Introduction
The application component provider
An application component provider is a developer who creates a component that is
intended to reside within one of the J2EE containers. The application component
provider develops application components adhering to the J2EE API specifications
with the intention that the component will be deployed within a J2EE Server. This
enables a developer to select a different J2EE product provider without modifying
the component. Application component providers develop a range of components,
including EJBs, HTML pages, and other Web components.
The application assembler
An application assembler generally uses various application components to create
a single application for distribution. Generally, in a large project, one team will be
responsible for developing the Web components, another for the business-logic
components, and perhaps another for the data-object components. The application
assembler would package the various components and then distribute them as an
enterprise archive (
.ear) file.
The deployer
The deployment of an enterprise application nearly always requires a different
configuration for each rollout. J2EE has taken this into consideration by specifying
the role of deployer. The deployer is responsible for configuring the applications
developed by the application assembler for execution within a platform provided
by the J2EE product provider.
The system administrator
A system administrator generally uses tools provided by a tool provider to monitor
the runtime environment and to ensure that services are performing optimally.
Various tools are available on the market, ranging from those which allow for moni-
toring the system as a whole, to runtime inspection on individual services to help
determine where bottlenecks may reside.
The tool provider
The J2EE specification also provides tools to make development easier and to moni-
tor the runtime environment. Tools vary from integrated development environments
to runtime-performance products.
The system-component provider
Many system components are available for the J2EE architecture. The J2EE archi-
tecture provides ways to introduce these new components for accessing services
such as existing messaging systems, transaction services, and others, such as
billing systems that may be industry-specific. Using the connector architecture is
one way to introduce these new components.
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