Start EAP 7 Enable statistics collecting for undertow (via CLI /subsystem=undertow:write-attribute(name=statistics-enabled, value=true) ) Deploy application with servlet which uses sessions (ideally setup session timeout to 1 minute), attached simple-servlet.war which contains such servlet Create request to that servlet curl -i http://127.0.0.1:8080/simple-servlet/counter -c cookie.txt -b cookie.txt wait for the session to expire (wait more than 1 minute, you can then try another request to see it has expired) check the statistics => run via CLI /deployment=simple-servlet.war/subsystem=undertow:read-resource(include-runtime=true) and see that session-avg-alive-time remains 0 even though expired-sessions has non zero value.