java - Stop threads before close my JavaFX program

Question

I'm having a problem with closing my application because some threads are still running after I close the application. Somebody can help me with some method to stop all Threads being executed in background before killing the main thread???

[EDITED]

With my questions about javafx I have noticed that many newer developers are facing problem managing Threads. I would like to share what I have done to simplify my life about managing threads on javafx. I've created an AsyncTask class based on AsyncTask from Android that basically do the same of Android's in a humble but effective way. You can find more information about it on Github project

Answer 1

You have three options here - the easiest is to simply create your Threads as deamons, which means that when your main program ends all deamon threads will terminate too.

Thread thread = new Thread();
thread.setDaemon(true);

Thats easiest, but the downside is that you wont get a graceful shutdown (ie the threads will stop, you wont get a chance to peform resource management etc, which may or may not be a problem for you).

The alternative is to keep a hold on the spawned threads and when your program receives the signal to close you iterate over the threads and pass in a signal of some sort to signa that they too should terminate

volatile boolean shutdown = false;

public void shutdown() {
   shutdown = true;
}

public void run() {
    while(!shutdown) { 
        ... do your work here
    }
    ... perform any cleanup work here

(Note: ignores any exception handling for clarity)

The last option is to use the Executor framework in java.util.concurrent

ExecutorService executorService = Executors.newFixedThreadPool(10);
... assign/invoke tasks etc

... at some point later your program is told to shutdown 
... shutdown in executor too 
executorService.shutdown();
executorService.awaitTermination(10, TimeUnit.SECONDS); // wait for 10s in this case
executorService.shutdownNow();