A minor irritation during Fedora startup cropped up recently - a failure in systemd-tmpfiles-setup.service.
[/etc/tmpfiles.d/jetty.conf:1] Unknown user 'jetty'.
It's caused by a bug in the post install script for jetty, documented in bug 857708. Either reinstall Jetty; or, if you installed it using the default settings & would rather take the quicker route, just finish things off yourself:
# groupadd -r -g 110 jetty
# useradd -r -u 110 -g jetty -d /usr/share/jetty -M -s /sbin/nologin jetty