adam bien's blog

Getting The Source Code For JavaFX UI 📎

Execute: hg clone http://hg.openjdk.java.net/openjfx/2.1/master/rt
and you will get the source for the JavaFX UI controls with a NetBeans project.

After adding a single class:

package com.sun.javafx;

public class PlatformUtil {

    public static boolean isMac() {
        throw new UnsupportedOperationException("Not yet implemented");
    }

    public static boolean isWindows() {
        throw new UnsupportedOperationException("Not yet implemented");
    }
    
}

and referencing the jfxrt.jar, the code becomes even compilable
Enjoy!