J2ME is a highly optimized Java runtime environment. J2ME is aimed at the consumer and embedded devices market. This includes devices such as cellular telephones, Personal Digital Assistants (PDAs) and other small devices.
| Profile(s) | |
| Configuration | Libraries |
| JVM | |
| Host Operating System | |
Java 2 Standard Edition (J2SE) developers should be familiar with Java Virtual Machines (JVMs) and at least one host Operating System (OS). Profiles and Configurations are introduced in J2ME.
The OS will vary on different handheld devices. Some devices run e.g. Symbian OS, others run some other OS developed by the manufacturer. It is therefore up to the manufacturers to implement a JVM for their specific platform compliant with the JVM Specification and Java Language Specification.
Handheld devices come with different form, features and functionality, but often use similar processors and have similar amounts of memory. Therefore configurations were created, defining groups of products based on the available processor power and memory of each device. A configuration outlines the following:
There are two standard configurations for the J2ME at this time, Connected Device Configuration (CDC) and Connected Limited Device Configuration (CLDC). The CDC is targeted toward powerful devices like Internet TVs and car navigation systems. The CLDC is targeted toward less powerful devices like mobile phones and PDAs.
A profile defines a set of APIs which reside on top of a configuration and offers access to device specific capabilities. The Mobile Information Device Profile (MIDP) is a profile to be used with the CLDC and provides a set of APIs for use by mobile devices. These APIs include classes for user interface, persistent storage and networking.
Specifications, APIs and other J2ME related information can be found at:
http://java.sun.com/j2me/
This page was last updated 14. Jul. 2006
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