April 21, 2011, 6:43 p.m.
posted by evil
Getting Information on MIDlet Suites
1 JAD File Attributes
The Java application descriptor (JAD file) is one way that an application developer provides information to the MIDP implementation. The MIDP implementation presents the information in the JAD file to the user to confirm that the user wants to install the MIDlet suite. The JAD file can also hold information for the MIDlets themselves. (The manifest of the JAR file can also provide information. See "JAR File Attributes" on page 196.)
If a JAD file is present, it must contain the MIDlet suite's name, version, vendor, JAR file URL, and JAR file size. It is permitted to contain a number of other attributes, such as a description of the MIDlet suite, and security-related information. (See the MIDP 2.0 Specification  for a full list of attributes; see Chapter 15 for more information on MIDP 2.0 security.)
There are three additional attributes that can only appear in a JAD file (if the application developer provides them at all). These attributes give the following pieces of information to the MIDP implementation:
2 JAR File Attributes
The manifest of the MIDlet suite's Java archive (JAR) file is one way that an application developer provides information to the MIDP implementation. The manifest of the JAR file must contain the MIDlet suite's name, version, and vendor. It is also permitted to contain other information, such as the required J2ME™ profile, the registrations for MIDlets to handle inbound connections, MIDlet-specific information, and so on. The information is provided as a list of attribute-value pairs. (See the MIDP 2.0 Specification  for a full list of attributes.)
3 Interactions of Attributes in the JAD and JAR Files
If the MIDlet suite includes a JAD file, three attributes (the MIDlet suite's name, version, and vendor) must be present in both it and the JAR file's manifest. Their values must be identical or the device cannot install the MIDlet suite.
Either the JAD file or the manifest of the JAR file must contain the required J2ME platform configuration and profile, as well as the name, class name, and optionally the icon for each MIDlet in the suite.