/usr/lib/jvm/java-7-openjdk-amd64/bin/servertool is in openjdk-7-jre-headless 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/bin/../jre/bin/servertool