Are there java or clojure mail libraries that do what lamson does? In particular, mail routing features for lamson are very cool. http://verpa.wordpress.com/2010/11/13/making-your-webapp-react-to-emails-with-lamson-pt-2/ is there anything similar for jvm?
JavaMail is quite complex and can send mail through STMP and receive using POP3 and IMAP. You can create a layer for routing letters yourself. Perhaps Apache JAMES is useful to you too.