UPDATED QUESTION:
I have a spring-boot 1.1.3.RELEASE project that is using EmbeddedTomcat and Spring-Security. I posted this a while back
Just to update this, because I went looking for an answer and couldn't find it easily:
You can set the server.session.cookie.max-age=
in your application.properties to force the log out after a certain time.
This one actually uses seconds, not minutes, as the integer value. So set it to something reasonable like 120 for 2 minutes.