I\'ve just upgraded to El Capitan and I\'m running into problems starting a custom JavaFX2 application running under JDK1.7.0u79 (the latest available from Oracle).
After more than a week with that in an extensive enterprise application, I haven't noticed any problems in the UI.
For the lack of a better solution, I'm accepting my update above as answer. Maybe it helps someone...
I've been able to get the app running again by adding this to the start of my main method.
try {
Class> macFontFinderClass = Class.forName("com.sun.t2k.MacFontFinder");
Field psNameToPathMap = macFontFinderClass.getDeclaredField("psNameToPathMap");
psNameToPathMap.setAccessible(true);
psNameToPathMap.set(null, new HashMap());
} catch (Exception e) {
// ignore
}