/usr/share/java/exec-maven-plugin.jar is in libmaven-exec-plugin-java 1.1.1+dfsg-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/java/../maven-repo/org/codehaus/mojo/exec-maven-plugin/1.1.1/exec-maven-plugin-1.1.1.jar