new Thread, application still running after Stage-close

Question

So I followed this tutorial: https://www.youtube.com/watch?v=gyyj57O0FVI

and I made exactly the same code in javafx8.

public class CountdownControll         


        

Answer 1

Part I

A thread, when created, runs independent of other threads. You have a new thread which has an infinite loop, which implies, it will keep running forever, even after the stage has been closed.

Normally, using a infinite loop is not advised, because breaking out of it is very difficult.

You are advised to use :

• TimerTask
• ScheduledExecutorService

You can then call either one of them (based on whatever you are using)

• TimerTask.cancel()
• ScheduledExecutorService.shutdownNow()

when your stage is closed. You can use something like :

stage.setOnCloseRequest(closeEvent -> {
       timertask.cancel();  
});  

JavaFX API's (thanks to James_D comment's)

These do not need to be explicitly canceled as ScheduledService uses daemon threads and AnimationTimer runs on the JavaFX thread.

• ScheduledService
• AnimationTimer

Part II

Your second part of the question has been answered time and again in the forum.

You need to be on the JavaFX Application thread to use scene graph elements.

Since you have created a new thread and trying to update label, which is a JavaFX node, it throws the exception. For more information, please visit:

JavaFX error when trying to remove shape

Why am I getting java.lang.IllegalStateException "Not on FX application thread" on JavaFX?

Javafx Not on fx application thread when using timer