Mobile application developers may have realize that one of the best (and recommended) way to distribute their JavaME/J2ME application is by hosting it on a website. This makes it easier for potential users to navigate and download the .jad or .jar files from their phone browsers and to execute it directly.
However, some web servers are not configured to handle .jar / .jad file requests, eventually leading to failed install response received by the mobile users.
To remedy this, .jad / .jar files need to be associated with the correct MIME type. In Apache, you can do this by creating ‘.htaccess’ file in your web directory, and inserting these lines :
AddType text/vnd.sun.j2me.app-descriptor .jad
AddType application/java-archive .jar
Afterwards, safe the file. The web server should behave accordingly when requests are made to either of these files. For other web servers, please refer to their respective manual or online-help on how to change document MIME type.