Pterodacty4J is a Java wrapper I wrote for the Pterodactyl panel, open source game panel software. My API wrapper is completely open source and is on GitHub so anyone can use it for themselves. This code fully wraps the Pterodactyl application and client APIs allowing anyone that is developing with Pterodactyl in Java the ability to do it much easier using my API wrapper.
You can go ahead and take a gander at the code on my Pterodactyl4J GitHub repository which can be found at https://github.com/mattmalec/Pterodactyl4J
You can learn more about Pterodactyl on their website at https://pterodactyl.io