/usr/share/java/regex.jar is in libregex-clojure 0.0~git20130321.1.433265f-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/java/regex-0.0~git20130321.1.433265f.jar
/usr/share/java/regex-0.0~git20130321.1.433265f.jar