/usr/lib/jvm/java-9-openjdk-amd64/src.zip is in openjdk-9-jdk-headless 9~b114-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/jvm/java-9-openjdk-amd64/../openjdk-9/src.zip
/usr/lib/jvm/java-9-openjdk-amd64/../openjdk-9/src.zip