[keycloak-user] How touser Servlet OAuth Client

Hi all, I'm trying to protect a servlet application which can be accessed either as anonymous user and as authenticated user. Some resources are protected and my application takes in charge the access control (not role based) so I can't use the war protection using role user constraint. In this case I've removed the role constraint in the web.xml and the keycloak wildfly (undertow) adapter let me access the application as unauthentified user (anonymous) which is perfect. What I want to handle on some AccessDeniedException is to redirect the user to the authentication server manually. In this case, user authentified an come back to the protected URL but is no more anonymous but a authentified user. Is ther is a way to handle this redirection to the authentication server manually (I don't know where to store the state variable allowing keycloak wildfly adapter to handle properly the auth redirect that include the code). Best regards, Jérôme.