CookieSessionFilter is a servlet filter which stores session data into the client cookie for Java based web applications.
In using CookieSessionFilter, session replication becomes unnecessary for multiplexing of application servers. You'll be able to make and manage multiplexing environment more easily.
It provides HttpSession interface. So any modification in your application is not necessary. Probably, you'll be able to use it with not so large cost.
See details about CookieSessionFilter at:
http://amateras.sourceforge.jp/site/cookie-session-filter/usage.html