If you plan to allow mobile gamers to download and play your mobile games from your site, you need to ensure that your web-server recognizes and returns the correct MIME type to the requesting mobile phone...
Configuring the server for JAD and JAR MIME types

Before you can use a server for OTA Provisioning, it must be configured to recognize the correct MIME types for JAR and JAD files.

* The MIME type for a JAR file is application/java-archive.
* The MIME type for the JAD file is text/vnd.sun.j2me.app-descriptor. This specifies the default character set to use (UTF- to convert the JAD file from its transport format to the correct MIDP Unicode-encoding.

For example,

* If you are using the Tomcat server delivered with JBuilder,
1. Find the file web.xml in the Tomcat install 'conf' sub-directory ( <JBuilder7_home>\jakarta-tomcat-4.0.3\conf).
2. Put the following lines in the section "Default MIME Type Mappings":

<mime-mapping>
<extension>jar</extension>
<mime-type>application/java-archive</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jad</extension>
<mime-type>text/vnd.sun.j2me.app-descriptor</mime-type>
</mime-mapping>

* If you are using an Apache server,
1. Find the file mime.types in the Apache install 'conf' sub-directory (<Apache>\conf\.)
2. Specify the JAD and JAR MIME types in the file as follows:
# MIME type Extension
application/java-archive jar
text/vnd.sun.j2me.app-descriptor jad

See your specific server documentation for directions on specifying MIME type configuration.