see JDK-8154171
when relaunching from JDK9 to 8u102 (or any JDK8) using FX toolkit.
the deploy dialogs that have an icon all get NPE in com.sun.deploy.uitoolkit.impl.fx.ui.resources.ResourceManager.getIcon().

to reproduce, install JDK9 and JDK8u102.
click on: http://oklahoma.us.oracle.com/www/tests/dialogs/jnlp/fx8.jnlp and hit button to show dialogs.
as you step thru the 13 dialogs in the FXUIToolkit, you can see NPE in console and trace file, and the dialogs will not have icons.