(09 Apr 2007)
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.
In Java ME it's the format in wich an application or game is distributed. It can be generated by a SDK, by a command-line tool, or by using an IDE, like NetBeans or Eclipse.
A Java ME JAR file can include:
- Compiled and preverified classes (MIDlet and other).
- Icons, graphics and images.
- Data information (records, localisation labels, game levels, etc.)
- Manifest file
A JAR file usually is distributed with a JAD file, describing what the JAR has.
MIDlet attributes must be the same in both JAR manifest and the JAD! Otherwise the application will not work after being signed.
For more information on signing and Java verfied see this FAQ
. In particular topics "Signing Java ME applications" and "Why doesn't my signed midlet work?"