Difference between JNLP and JavaFX
Both the applet and webstart methods use JNLP files to deploy JavaFX applications.
This is a change from the past when JNLP was only used by WebStart (which is what you refer to).
There isn't much of a difference, it depends on the user experience you want the user to have. I would say that for the most significant applications, you are better off using the more traditional method of launching websites (download a JNLP file from a link and run its javaws).
There are minor differences in security privileges between an applet and a web start, as well as more API differences within JavaFX between what runs in the applet and what runs in the running web browser of the application. They are slowly being eliminated.
source to share
I think you are mixing things up.
JNLP is just a way to deploy your application, while JavaFX is the presentation layer.
You can actually deploy your JavaFX code in a JNLP package.
You should compare JavaFX to Swing;)
With JNLP, you can distribute Java Swing or AWT or SWT or JavaFX applications. Having the ability to execute then in the sandbox.
source to share