A JAR File (Java ARchive) is a ZIP file used to distribute a set of Java classes. It is used to store compiled Java classes and associated metadata that can constitute a program.
A Java ME JAR file can include:
- Compiled and preverified classes (MIDlet and other).
- Icons, graphics and images.
- Data information (records, internationalization labels, game levels, etc.)
- Manifest file
A JAR file usually is distributed with a JAD file, describing what the JAR has.