I am trying to run a JAR file and it seems to have a dependency on JavaFX. It does not appear to me that there is any JavaFX or OpenJFX package on software.opensuse.org. What is the proper way to install this?
You could get JavaFX from Oracle JDK. Unfortunately JavaFX is not a part of the OpenJDK package for OpenSUSE, but you can get it here. There you can find instructions how to get and build OpenJFX. Does not looks like anyone has prebuild OpenJFX packages for OpenSUSE.