/usr/share/maven-repo/org/eclipse/jdt/core/compiler/ecj/debian/ecj-debian.jar is in libecj-java 3.5.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/maven-repo/org/eclipse/jdt/core/compiler/ecj/debian/../../../../../../../../java/eclipse-ecj-3.5.1.jar