That's not possible using the standard Realms that ship with Tomcat. But you could extend JDBCRealm, add some notification mechanism to it, and configure Tomcat to use that instead of JDBCRealm. Details on how to get started with a custom Realm
are here.
It's also possible to obtain at runtime the Realm object that Tomcat uses, but you would need to utilize Tomcats internal API, and it doesn't solve your problem by itself. The details
can be found here if you're curious.
[ September 14, 2005: Message edited by: Ulf Dittmer ]