"trustin" wrote : | Hmm, or MINA could provide a concurrent hash map backed implementation out of the box (although it will not be the default). | I like the idea of MINA having some config switch boolean "useConcurrentSessionMap" which if true uses a ConcurrentHashMap and if false uses the synchronized map. Then the user can choose which to use based on their number of expected connections and available RAM. This can default to false to preserve current behaviour. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4149825#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...