AddType application/x-java-archive .jar
AddType application/x-java-jnlp-file .jnlp

<Files *.jar.pack.gz>
  AddEncoding pack200-gzip .jar
  RemoveEncoding .gz
</Files>

RewriteEngine on
RewriteCond %{HTTP:Accept-Encoding} pack200-gzip
RewriteCond %{REQUEST_FILENAME}.pack.gz -f
RewriteRule ^(.*\.jar)$ $1.pack.gz [NC,L]

RewriteCond %{HTTP:Accept-Encoding} gzip
RewriteCond %{REQUEST_FILENAME}.gz -f
RewriteRule ^(.*\.jar)$ $1.gz [NC,L]