The Complete Reference J2ME text book
Java technology has evolved from a programming language designed to create machine-independent embedded systems into a robust, vendor-independent, machine-independent, server-side technology, enabling the corporate community to realize the full potential of web-centric applications.
Java began with the release of the Java Development Kit (JDK). It was obvious from the start that Java was on a fast track to becoming a solution to the problems of many corporate systems.
More interface and libraries were extended in the JDK as the corporate world demanded—and received—application programming interfaces (API) that addressed real-world situations.
JDK API extensions fully integrated into the JDK with the release of the Java 2 Standard Edition (J2SE) of the JDK. J2SE contains all the APIs needed to build industrial strength Java applications.
However, the corporate world felt J2SE lacked the strength required for developing enterprise-wide applications and for servicing the needs of developers of mobile and embedded systems.
Again the corporate community pushed Sun Microsystems, Inc. to revise Java technology to address needs of an enterprise.
Sun Microsystems, Inc. then launched the Java Community Program (JCP) that brought together corporate users, vendors, and technologists to develop a standard for enterprise Java APIs. The result is the
Java 2 Platform Enterprise Edition, commonly referred to as Java 2 Enterprise Edition
(J2EE), and the Java 2 Micro Edition (J2ME).
Enterprise systems traditionally are designed using the client/server model, where
client-side systems request processing from service-side systems. However, enterprise
systems were undergoing their own evolution.
Anew model calledWeb services gradually replaced the client/server model in corporations.
Application programmers assembled applications from an assortment of processing
components called Web services. Each Web service was independent from other Web
services and independent from applications. A client-side application communicates
with a middle-tier, server-side application, which in turns interacts with the necessary
Web services that are also located on the server side.
With the adoption of the Web services model in corporations, the JCP realized that
J2ME must also go through another evolutionary cycle. With the introduction of new
specifications, the Java community has merged J2ME technology with Web services
technology.
In addition to the acceptance ofWeb services, corporations are also seeking to merge
mobile technology such as Personal Digital Assistants and cellular phones with
corporate mainstream applications. J2ME, with the new PIM API, enables developers
to create sophisticated, wireless applications that have direct access to native PDA
databases. This enables corporate executives to use corporation’s PDA systems to
interact with data mantained by PDA native applications.
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