Java application descriptor Filename extension .jad
Internet media type text/vnd.sun.j2me.app-descriptor
Developed by Sun Microsystems, Inc.
Type of format Descriptor file
Standard(s) Java application
Java Application Descriptor (JAD) files describe the MIDlets (Java ME applications) that are distributed as JAR files. JAD files are commonly used to package Java applications or games that can be downloaded to mobile phones. Java applications enable mobile phones to interact functionally with online web services, such as the ability to send SMS messages via GSM mobile Internet or interact in multiplayer games. Some BlackBerry devices use JAD files for themes.
Recent midlets contain a manifest file in the JAR archive. This file contains much of the information stored in the JAD file, rendering it unnecessary in most cases.
The MIDP2 specification instructs that web servers should serve JAD files with a MIME type of "text/vnd.sun.j2me.app-descriptor". If this MIME type is not correctly configured, many phones will fail to install the MIDlet.