I was waiting for someone to respond, but nobody wants to say anything, it seems.
Personally, I'd RTFM on the LockoutRealm in the Tomcat docs at tomcat.apache.org. If you have questions about what it says, ask us.
Some people, when well-known sources tell them that fire will burn them, don't put their hands in the fire.
Some people, being skeptical, will put their hands in the fire, get burned, and learn not to put their hands in the fire.
And some people, believing that they know better than well-known sources, will claim it's a lie, put their hands in the fire, and continue to scream it's a lie even as their hands burn down to charred stumps.