JavaFX uses the recently-deprecated (see JDK-8276408) single string variant of the Runtime::exec method in the following places:

modules/javafx.graphics/src/main/java/com/sun/javafx/application/HostServicesDelegate.java:
   137 if (osName.startsWith("Mac OS")) {
   138 Runtime.getRuntime().exec(
   139 "open " + uri);
   140 } else if (osName.startsWith("Windows")) {
   141 Runtime.getRuntime().exec(
   142 "rundll32 url.dll,FileProtocolHandler " + uri);

We should replace these calls with Runtime::exec(String[])