/usr/lib/jvm/java-7-openjdk-amd64/demo/applets is in openjdk-7-demo 7u181-2.6.14-1~deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/jvm/java-7-openjdk-amd64/demo/../../../../share/doc/openjdk-7-jre-headless/demo/applets