What is J2ME?
Java 2 Micro Edition is the edition of the Java 2 platform targeted at wireless and embedded devices. J2ME is the evolutionary version of java. J2ME is highly optimized java runtime environment

Key features
J2ME provides a range of virtual machines, optimized for different processors types and memory footprints.

Application
J2ME technologies are based on configurations and profiles. A configuration defines the minimum set of class libraries available for a range of devices. A profile defines the set of APIs available for a particular family of devices. For example, the profile for the cell phone vertical market is separate from the profile for the personal organizer vertical market, but both profiles work with the same configuration.
For more details refer to www.sunmicrosystems.com