After using NGASI App Manager for several years, we were pretty unhappy to learn they were going out of business.
We took the opportunity to develop our own Java provisioning system, CoffeeCP.
CoffeeCP is available for cPanel, as well as Virtualmin and Webmin (with other control panels soon to come).
It can be provisioned via WHMCS or directly on your servers.
Unlike NGASI, CoffeeCP is not a Java application itself, so it has a very small footprint.
Also unlike NGASI, it is not a separate control panel, users access all functions via cPanel, Webmin, etc..
The cPanel version is built with JSON and PHP and the Virtualmin and Webmin versions are built with Perl.
So, no extra overhead.
If you are or were a NGASI user, or just want to add Java to your hosting offerings, have a look at CoffeeCP
All plans include Unlimited Installations, so you also have the benefit of a fixed monthly overhead and won't need to buy additional licenses for each VM or server you turn up.