This video will explain how to enable VPL with JAVA libraries on Moodle 3.6 (in Hebrew)
Example of VPL Code in JAVA for Moodle: https://blog.devlion.co/wp-content/uploads/moodle-java-vpl-example.zip
Example VPL Server Configuration on Ubuntu 18.08: https://github.com/devlionco/bashscripts/blob/master/install_vpl_ubuntu_18_08.sh
Documentation of VPL SERVER: https://vpl.dis.ulpgc.es/index.php/support/2014-09-27-15-06-22/40-how-to-install-vpl-jail-system
Moodle plugin vpl: https://moodle.org/plugins/mod_vpl