Java 2 Mobile Edition

 
 
The Micro Edition is targeted at a range of consumer and embedded electronic devices with constrained resources.

The Micro Edition itself is subdivided into configurations targeted at particular hardware configurations. The most appropriate configuration for cell phones is the Connected Limited Device Configuration CLDC, (160-512 KB memory available for Java, battery powered, slow, possibly intermittent, connection). Sitting on top of the CLDC is the Mobile Information Device profile (MIDP) which specifies an API set appropriate for mobile information devices such as phones.

More information about J2ME can found at: http://java.sun.com/javame/index.jsp

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Manifest and JAD attributes.



Information
A JAR META-INF/MANIFEST.MF file and a JAD file contains several optional and mandatory attributes, based on MIDP 2.0, JSR 118.


Attribute name MANIFEST.MF JAD Description
MicroEdition-Configuration must must Must be the same format and value as the System property microedition.configuration.

For example: CLDC-1.0
MicroEdition-Profile must must Must be the same format and value as the System property microedition.profiles.

For example: MIDP-2.0
MIDlet-<n> must must The name, icon, and class of the <n> midlet in the JAR file separated by a comma. The name and class are mandatory.

For example 1:
Demo, /icons/simpledemo.png, com.mobilefish.Demo

For example 2:
Demo, , com.mobilefish.Demo

The attribute must occur in MANIFEST.MF or JAD or either, but is not optional.

<n> is an integer, starting at 1 and incremented by 1 for each midlet.
MIDlet-Data-Size may may The minimum number of bytes of persistent data required by the MIDlet suite.

For example: 500
MIDlet-Delete-Confirm may may The application management system uses this confirmation prompt when removing the MIDlet suite.

For example:
Are you sure you want to delete the Demo?
MIDlet-Delete-Notify may may This property indicates the URL for posting removal status.

The deletion of a MIDlet suite is of interest to the company providing the MIDlet suite. When the user deletes the MIDlet suite a deletion report is send.

For example: http://www.mobilefish.com/ota.php?a=d&k=36
MIDlet-Description may may The MIDlet suite description.

For example: A simple demo midlet
MIDlet-Icon may may The case-sensitive absolute name of a .png file within the JAR used to represent the MIDlet suite.

For example: /icons/mydemo.png
MIDlet-Info-URL may may The URL where more information can be found describing the MIDlet suite.

For example:
http://www.mobilefish.com/midlets/demo.html
MIDlet-Install-Notify may may Indicates the URL for posting installation and update status.

The success or failure of the installation and upgrade of a MIDlet suite is of interest to the company providing the MIDlet suite. When the user installs the MIDlet suite an installation report is send.

For example: http://www.mobilefish.com/ota.php?a=i&k=36
MIDlet-Jar-Size   must The JAR file size in bytes.

For example: 3711
MIDlet-Jar-URL   must The URL from which the JAR file can be loaded. Both absolute and relative URLs MUST be supported. The context for a relative URL is the URL from which this application descriptor was loaded.

For example:
http://www.mobilefish.com/midlets/Demo.jar
MIDlet-Name must must The name of the MIDlet suite.

For example: Show a demonstration
MIDlet-Permissions-Opt may may Zero or more permissions that are non-critical to the function of the MIDlet suite.

If any one of the non-critical permissions defined in this field is not supported by the phone, then the phone ignores the permissions and installs the MIDlet suite.

For example:
The MIDlet suite may use a HTTPS connection, but it is not vital to function.

javax.microedition.io.Connector.https
MIDlet-Permissions may may Zero or more permissions that are critical to the function of the MIDlet suite.

If any one of the critical permissions defined in this field is not supported by the phone, then the phone will not install the MIDlet suite.

For example:
The MIDlet suite requires a HTTP and HTTPS connection to function.

javax.microedition.io.Connector.http,
javax.microedition.io.Connector.https
MIDlet-Push-<m> may may To push data from the server and launch a mobile application automatically in the device, without the device being explicitly started by the user. The push connection has the following format: <ConnectionURL>, <MIDletClassName>, <AllowedSender>

Where:
<ConnectionURL>
The connection string used in Connector.open().

<MIDletClassName>
The MIDlet responsible for the connection, see MIDlet-<n>

<AllowedSender>
A filter that restricts which senders are valid for launching the requested MIDlet.

For example 1:
datagram://:444, com.mobilefish.Demo, 64.233.167.99

For example 2:
socket://:444, com.mobilefish.Demo, *

Note:
<m> is an integer, starting at 1 and incremented by 1 for each Push Registry entry.
MIDlet-Vendor must must The company that provides the MIDlet suite.

For example: Mobilefish.com
MIDlet-Version must must The MIDlet suite version number.

For example: 1.0.1