230 WCTME: Application Development and Case Study
8.1 Overview
When deployed, an application consists of a customizable Java Class Library
(JCL) and JVM, the SMF environment, System application services, bundles and
the application bundles themselves.
8.1.1 Configuring the Java Class Library (JCL)
The JCL profiles, which include the IBM J9 JVM, allow the developer of a micro
environment application to customize the java platform to include only the
features that are needed by the system and application bundles. For applications
that require the java powered brand and standard, the Studio tool continues to
offer developers the options of choosing J2ME profiles since WCTME tooling
includes all the tooling capabilities of WebSphere Studio Device Developer.
8.1.2 Configuring the bundle application using the SMF
The SMF environment and the application services are deployed as bundles on
top of the JVM. As illustrated in Figure 1-1 of Chapter 1, “Introduction to
Workplace Client Technologies” on page 1, the SMF adds many configuration
capabilities to the java platform for mobile environments.
The SMF environment can be configured to run many applications or services,
unlike a stand-alone JVM which can only run one application. This is carried out
by applications being installed as bundles that have zero or many services.
These services can be administered using the SMF environment. Unlike the
closed container in a J2EE environment, the SMF environment allows the
sharing of services amongst other bundle applications. It implements this feature
using a manifest where the services and bundle exports and imports are
declared. The SMF also administers the life cycle of these bundles.
8.1.3 Adding system application services
The list of system services that a custom application can use does vary,
depending on the WCTME platform profile. All of the services that WCTME
makes available to the java application take the form of a service bundle such as
the DB2 Everyplace ISync Client. Even the SMF environment is a mandatory
application service bundle.
The following chapter describes how to use the platform builder to include
additional SMF application services, custom services and to expose the bundle
services to other bundles. The platform builder can also be used to create a
custom Java class library containing the features that the bundles need so that
the restricted resources of a mobile environment are used most efficiently.

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