With apache it is possible to have a reverse proxy with AJP instead of http. With the use of mod_proxy_ajp it is very simple to set up and faster than just plain http protocol

<VirtualHost *:80>
    ServerName jenkins
    DocumentRoot "/mario/Apache22/htdocs"
    <Directory "/mario/Apache22/htdocs">
        Options Indexes Includes FollowSymLinks
        AllowOverride All
        Order Allow,Deny
        Allow from all
        Deny from none
    </Directory>
    <Location />
        ProxyPass ajp://localhost:8009/
        ProxyPassReverse ajp://localhost:8009/
    </Location>

    SetEnv vhostname jenkins
    Header add X-Server-Name %{vhostname}e
</virtualhost>

Than start the backend server, in this case only with AJP and listen only on localhost

java -jar jenkins.war --httpPort=-1 --ajp13ListenAddress=127.0.0.1