Thursday, November 29, 2007

What is a Java application?

Any standard series 40 and series 60 phone has a built-in Java environment which allows you to run all sorts of fresh applications and games. The installation and management of such applications is easy, once you know how to do it.

A MIDlet is a Java application that conforms to the Mobile Information Device Profile (MIDP) standard. The MIDP specification defines the Java Virtual Machine and API available on most Java-enabled smart phones, including all Nokia smartphones.

Java technology is widely used to develop mobile games and entertainment applications for Nokia phones. In fact, your Nokia was probably preinstalled with a few Java games (eg Golf and Beach Rally) and utilities (for example, and the converter Clock), courtesy of Nokia and your wireless operator. Here is a list of Web sites where you can buy or download MIDlets:

Handango is the largest online store for mobile software. It runs Nokia and Motorola online software stores. Visit to http://www.handango.com/ Handango.

The mpowerplayer website (http://www.mpowerplayer.com/) provides "previews" of mobile Java games right on your computer screen. You can download a game and play it on your computer. You just have to pay for the game once you choose to install on your phone. It is nice. Try!

The Midlet Review (http://www.midlet-review.com) publishes reports and evaluations of new MIDlets, especially games.

A Java application consists of two files. Java Archive (JAR) file contains the application executable code. Descriptor Java application (JAD) file is a text file containing the attributes of the application and the location of JAR file. During the installation process, the phone went to the JAD file, analyzes its contents, and checks whether the device has the required software and storage space to install the application. If everything looks OK, the camera follows the URL in the JAD file to locate and download the JAR file. Then, the camera compares the JAR file with attributes in the JAD file (for example, application name, vendor, size, digital signature, and so on.) If everything is, the application is installed and becomes the disposal.

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