/usr/lib/jvm/java-7-openjdk-amd64/docs is in openjdk-7-jre-headless 7~u3-2.1.1~pre1-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/jvm/java-7-openjdk-amd64/../../../share/doc/openjdk-7-jre-headless