Hello, I had a problem implementing JAAS with Tomcat and I found my error, I was specifying my custum loginModule in the <realm (server.xml) and not in the JAAS.conf file. Can you tell me which classname of realm I need to use : <Realm className="org.apache.catalina.realm.JAASRealm" appName="appJAAS" userClassNames="com.app.security.User" roleClassNames="com.app.security.Role" debug="99"/> (I want to create a index.jsp page with 2 fields (login, pwd) and use the j_security_check). Thanks again