To Apache Web Server correctly handles yours JNLP (Java Network Launch Protocol) files, modify or create a .htaccess file in the top directory of your web site and add the following:
AddType application/x-java-jnlp-file   .jnlp AddType application/x-java-archive-diff .jardiff
Without these MIME-types, the user would see the xml jnlp file as a plain text in the browser. After that you can link to yours Java Web Start applications with a icon like this one:
