/usr/share/maven-repo/org/bouncycastle/bcmail/1.56/bcmail-1.56.jar is in libbcmail-java 1.56-1+deb9u2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/maven-repo/org/bouncycastle/bcmail/1.56/../../../../../java/bcmail-1.56.jar