Ubuntu 18.04 - doesn't even start.

[Barleduq]

I downloaded the minion java files, and put them in my home directory.
I thought I had java installed. My first set of errors were

sudo apt install default-jre
sudo apt install openjdk-11-jre-headless
sudo apt install openjdk-8-jre-headless

I installed all three. Now my error is

CLI#: java -jar Minion-jfx.jar
Error: Could not find or load main class gg.minion.Minion
Caused by: java.lang.NoClassDefFoundError: javafx/application/Application

I'm an experienced user, but not with java. Suggestions are welcome.
-Barleduq