I'm not sure how the command prompt/terminal command will have to change, but I got the jar here working on Ubuntu using Java 11 (specifically OpenJDK).
Since it wouldn't let me just double-click execute it, I had to try running it with:
Code:
java -jar lt_0.4.7.5_pr.jar
That didn't work for me, since it said it was missing Java classes, so I had to add where the modules were installed and list the modules that it needs to run.
Code:
java --module-path /usr/share/openjfx/lib/ --add-modules javafx.base,javafx.fxml,javafx.controls,javafx.web -jar lt_0.4.7.5_pr.jar
The 'module-path' part will probably need to change if you're not on Linux, and I'm not sure where windows specifically installs Java.
Hopefully this help puts you in the right direction.