The ServletContextListener is a
J2EE standard service that is employed whenever a webapp goes up or down. So for Jetty not to act just like Tomcat, Jetty would have to update the WAR without stopping it. Which is a questionable thing to do.
Beyond that, if you are creating files within the WAR, you are violating the J2EE standards and playing with fire. DON'T DO IT. Yes, I know it works in a lot of different versions and brands of servers when certain options are in effect. But just because you can do something, doesn't mean it's safe to do if the standard doesn't support it. And this is very definitely unsafe. I think in fact, you're trying to kludge around that very lack of safety.
You would be far better off if you designated a directory that's totally external to both your war and the webapp server itself to hold mutable files in.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.
