Java 2 SDK 

The Java 2 Platform

A platform is the hardware or software environment in which a program runs.  some of the most popular platforms like Microsoft Windows, Linux, Solaris OS, and Mac OS. Most platforms can be described as a combination of the operating system and underlying hardware. The Java platform differs from most other platforms in that it's a software-only platform that runs on top of other hardware-based platforms.

The Java platform has two components:

• The Java Virtual Machine
• The Java Application Programming Interface (API)

What we commonly refer to as "Java" is more formally known as the Java 2 Platform. The Java 2 Platform is split into three editions:

   1. Java 2 Standard Edition (J2SE),

   2. Java 2 Enterprise Edition (J2EE), and

   3. Java 2 Micro Edition (J2ME).

The various specifications that comprise J2ME are all defined through the Java Community Process (JCP), as is done with J2SE and J2EE. Today, there are close to forty separate Java Specification Requests (JSRs) dealing with J2ME: Small device programming is definitely a hot topic within the Java community.

Java 2 Micro Edition Overview

Java Platform, Micro Edition (Java ME) is a collection of technologies and specifications to create a platform that fits the requirements for mobile devices such as consumer products, embedded devices, and advanced mobile devices. It is a collection of technologies and specifications that can be combined to create a complete Java runtime environment specifically to fit the requirements of a particular device or market.

 

Java ME technology was originally created in order to deal with the constraints associated with building applications for small devices. For this purpose Sun defined the basics for Java ME technology to fit such a limited environment and make it possible to create Java applications running on small devices with limited memory, display and power capacity.

Java ME platform is a collection of technologies and specifications that can be combined to construct a complete Java runtime environment specifically to fit the requirements of a particular device or market. This offers a flexibility and co-existence for all the players in the eco-system to seamlessly cooperate to offer the most appealing experience for the end-user.

The Java ME technology is based on three elements;

• a configuration provides the most basic set of libraries and virtual machine capabilities for a broad range of devices,
• a profile is a set of APIs that support a narrower range of devices, and
• an optional package is a set of technology-specific APIs.

Over time the Java ME platform has been divided into two base configurations, one to fit small mobile devices and one to be targeted towards more capable mobile devices like smart-phones and set top boxes.

The configuration for small devices is called the Connected Limited Device Configuration (CLDC) and the more capable configuration is called the Connected Device Profile (CDC).

In J2ME, the Java runtime environment is adapted for constrained devices - devices that have limitations on what they can do when compared to standard desktop or server computers. For low-end devices, the constraints are fairly obvious: extremely limited memory, small screen sizes, alternative input methods, and slow processors. High-end devices have few, if any, of these constraints, but they can still benefit from the optimized environments and new programming interfaces that J2ME defines.

-- Er. R.G.Yaadav., M.Tech., MCSD., SCJP