Question

I have some code which adds a Java FX WebView to a JFrame. This works great. Once the user has visited a specific website, I’m trying to programatically close this JFrame, first by calling Platform.exit() and then frame.dispose(). This works fine as long as I call this method from the same thread that the WebView was started from.

However, this is what I am trying to avoid. Consider the following code (http://pastebin.com/kAjweLi5).
This code tries to shut down the program when the URL changes. However, this results in:

IllegalStateException: Attempt to call defer when toolkit not running
(stacktrace)

Update:
Using my (very limited) debuggning knowledge, I realized that the exit() method seems to successfully run. Image of the stack:

(the error occures when the yellow line is executed)

How can I close the JFrame from another thread/class, without getting the above exception?

Answer 1

From previously (amended) post:

public void exit()
{
   Platform.runLater( new Runnable(){@Override public void run(){
      System.err.println( "exit/runLater/run" );
      webEngine.getLoadWorker().cancel();
      Platform.exit();
      SwingUtilities.invokeLater( new Runnable(){ @Override public void run() {
         System.err.println( "exit/invokeLater/run" );
         frame.dispose(); }});
      }});
}

It’s necessary to shutdown background threads