what is require for action with J2ME

what is J2ME?

the name of god the merciful.

Java Platform, Micro Edition (Java ME) provides a robust, flexible environment for applications running on mobile and other embedded devices—mobile phones, personal digital assistants (PDAs), TV set-top boxes, and printers. Java ME includes flexible user interfaces, robust security, built-in network protocols, and support for networked and offline applications that can be downloaded dynamically. Applications based on Java ME are portable across many devices, yet leverage each device's native capabilities.  please visit sun

Let's begin with a quick summary of the Java platforms currently available:
• Standard Edition (J2SE): Designed to run on desktop and workstations computers.
• Enterprise Edition (J2EE): With built-in support for Servlets, JSP, and XML, this edition is
aimed at server-based applications.
• Micro Edition (J2ME): Designed for devices with limited memory, display and processing
power.
Note
In December of 1998, Sun introduced the name "Java 2" (J2) to coincide with the
release of Java 1.2. This new naming convention applies to all editions of Java,
Standard Edition (J2SE), Enterprise Edition (J2EE), and Micro Edition (J2ME).

 Why J2ME?
J2ME is aimed squarely at consumer devices with limited horsepower. Many such devices (e.g., a
mobile phone or pager) have no option to download and install software beyond what was configured
during the manufacturing process. With the introduction of J2ME, "micro" devices no longer need to
be "static" in nature. Not unlike a web browser downloading Java applets, an implementation of J2ME
on a device affords the option to browse, download and install Java applications and content.
Small consumer electronics have a way of changing our lives. Mobile phones let us communicate
when away from our home or office. Personal digital assistants (PDAs) let us access email, browse the
internet and run applications of all shapes and forms. With the introduction of Java for such devices,
we now have access to the features inherent to the Java language and platform. That is, a
programming language that is easy to master, a runtime environment that provides a secure and
portable platform and access to dynamic content, not to mention an estimated developer community of
over 2 million people.
Although it would be nice to have the entire J2SE Application Programming Interface (API) available
on a micro device, it's not realistic. For example, a mobile phone with its limited display cannot
provide all the functionality available in the Abstract Window Toolkit, the first graphical user
interface released with Java. The "Micro Edition" was introduced to address the special needs of
consumer devices that are outside the scope of J2SE and J2EE.
The capabilities of devices within the "Micro Edition" may vary greatly. An Internet Screenphone (a
hardware device designed to provide access to email, news, online banking, etc.) may have a much
larger display than a pager. However, even devices that seem similar in size may vary greatly in their
capabilities. A cell phone and PDA are both limited in physical size, yet a typical cell phone may have
a display with a total resolution of 12,288 pixels (96 x 128), whereas a PDA resolution may start at
20,000 pixels and go up from there.
3
One Java platform will most definitely not fit all. To better understand how J2ME will accommodate a
broad range of consumer electronics and embedded devices, we need to introduce two new concepts,
configurations and profiles.

Configurations

To support the broad range of products that fit within the scope of J2ME, Sun introduced the

Configuration.

A Configuration defines a Java platform for a broad range of devices. A Configuration is closely tied

to a Java Virtual Machine (JVM). In fact, a Configuration defines the Java language features and the

core Java libraries of the JVM for that particular Configuration.

The dividing line as to what a Configuration applies is for the most part based on the memory, display,

network connectivity (or limitations of) and processing power available on a device.

The Sun J2ME FAQ states the following: "The J2ME technology has two design centers—things that

you hold in your hand and things you plug into a wall." This may be a good general definition, but

that's exactly what it is, general. Don't let this be your sole guide in deciding which Configuration

applies.

Following are typical characteristics of devices within the two currently defined Configurations:

Connected Device Configuration (CDC)

• 512 kilobytes (minimum) memory for running Java

• 256 kilobytes (minimum) for runtime memory allocation

• Network connectivity, possibly persistent and high bandwidth

Connected, Limited Device Configuration (CLDC)

• 128 kilobytes memory for running Java

• 32 kilobytes memory for runtime memory allocation

• Restricted user interface

• Low power, typically battery powered

• Network connectivity, typically wireless, with low bandwidth and intermittent access

Although this division seems pretty clear, this won't always be the case. Technology is continually

advancing. Remember your first computer? What was "state-of-the-art" in 1985 (when I purchased my

first personal computer) pales in comparison to what is available today.

The point is, as technology offers us more processing power, with increased memory and screen

capabilities, the overlap between these categories will become larger. This is a nice segue to our next

discussion, Profiles.

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god bless