/usr/share/java/jetty8-jmx.jar is in libjetty8-java 8.1.3-9.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/java/jetty8-jmx-8.1.3.v20120416.jar
/usr/share/java/jetty8-jmx-8.1.3.v20120416.jar