After a fix for JDK-8005465 FX and AWT can be started in any order, both headful. However, there's still some minor problems remain with the order of termination (JDK-8006320).

In terms of this Enhancement, we would like to introduce a protocol, most likely internal, for several GUI Java toolkits to co-exist in one JVM, and be able to terminate gracefully no matter which of toolkits finishes first.

The first attempt was made with a fix for JDK-8005465 (see http://mail.openjdk.java.net/pipermail/awt-dev/2012-December/004018.html). The proposed solution suggested to initiate an activity on the native event loop which would indicate that a toolkit is still alive, and hence the app as a whole should not be terminated yet.

However, this solution isn't ideal for battery-powered devices. We might want to explore other possibilities. E.g. introduce a Java class (sun.misc.GUITermiantion or alike), and establish a protocol for GUI toolkits to maintain a usage counter through this new class. Once the counter goes down to zero, an event will be fired which would allow the main (embedder) toolkit to terminate the whole application.