JAVA 2 MICRO EDITION (J2ME) TECHNOLOGY

JAVA 2 MICRO EDITION (J2ME) TECHNOLOGY

1 INTRODUCTION

On the 15th of June 1999, Sun Microsystems announced a redefined architecture for the Java™ platform at the Java One conference in San Francisco.
The architecture was targeted to a wide variety of markets and at the same time expected to provide developers, service providers and device manufacturers extra benefits by making it simpler and specific to the market.J2ME is a set of J2SE & J2EE.

1.1 Basic constraints of Java Technologies

Each Java™ edition defines a set of technology and tools that can be used with a particular product:
• Java virtual machines that fit inside a wide range of computing devices;
• libraries and APIs specialized for each kind of computing device; and
• tools for deployment and device configuration.

There are mainly 3 editions of the Java Technology.
1. Java 2 Standard Edition (J2SE),
2. Java 2 Enterprise Edition (J2EE),
3. Java 2 Micro Edition (J2ME).

1.2 Overview of J2SE & J2EE

1.2.1 Java 2 Standard Edition (J2SE)

J2SE is a feature complete development and deployment foundation for building client side enterprise applications. These applications include both web applications such as applets and standalone desktop applications. In addition to standard components of Java platform (JVM, Java programming language, Java packages) J2SE includes java applet viewer, java debugger and other tools. One of such tools found in version 1.3 of J2SE is Java plug-ins. J2SE platform consists of two binary deliverables: Java 2 Standard Development Kit (JDK) and Java 2 Runtime Environment (JRE). JDK consists of Java compiler and is used for application development whereas JRE consists of only those components, which are mandatory in running a Java application or a Java applet.

1.2.2 Java 2 Enterprise Edition (J2EE)

J2EE is a foundation for server side of enterprise application development. Traditionally, enterprise applications are based on two-tier model, generally the client and the server. As the complexity of the applications grow tremendously and the customers demand flexibility, the two-tier applications model started to migrate to a multi-tier application model. In a multi-tier model, the business logic is kept separate from both the client side user interface and the server side system services and it occupies the middle tier(s). The server side system services can be either new services or some existing Enterprise Information Systems (EIS). These middle tiers take the role of middleware and provide services to both the client-tier and EIS-tier without them knowing the details of how these services are implemented. J2EE architecture is based on multi-tier model. The client user interface is implemented as the first tier, the EIS tier stores business critical data and the middle tier implements enterprise services such as database access, Common Gateway Interface (CGI) behavior and implementation of easily configurable and reusable components as multi-tier applications. These multi-tier applications are expected to provide scalability, accessibility and manageability. In order to achieve this model, the J2EE platform provides a lot of standard system services whereas the developers are responsible for implementing business and presentation logic.

1.3 Introduction to Java™ 2 Platform Micro Edition (J2ME™)

To meet the demand for information appliances in the rapidly developing consumer and embedded markets, Sun has extended the scope of Java technology with the introduction of Java™ 2 Platform, Micro Edition (J2ME™) technology.
The versatility of the Java application development environment is now enabling the development of many new and powerful information appliance products. Java technology enables users, service providers, and device manufacturers to take advantage of a rich portfolio of application content that can be delivered to the user’s device on demand, by either physically connected (wired) or wireless connections.
Java 2 Micro Edition (J2ME™)—for the combined needs of:
1. Consumer and embedded device manufacturers who build a diversity of information devices.
2. Service providers who wish to deliver content to their customers over those devices.
3. Content creators who want to make compelling content for small, resource-constrained devices.