<ProgressIndicator fx:id="progressIndicator" opacity="0.64" progress="-1.0">
      <StackPane.margin>
        <Insets bottom="100.0" left="100.0" right="100.0" top="100.0" />
      </StackPane.margin>
</ProgressIndicator>

public abstract class BackgroundTask<T> extends Task<T> {
    static Map<ProgressIndicator, AtomicInteger> indicatorMap = new HashMap<ProgressIndicator, AtomicInteger>();

    protected BackgroundTask(final ProgressIndicator indicator) {
        startIndicator(indicator);
        setOnFailed(new EventHandler<WorkerStateEvent>() {
            @Override
            public void handle(WorkerStateEvent workerStateEvent) {
                stopIndicator(indicator);
                Throwable exception = workerStateEvent.getSource().getException();
                exception.printStackTrace();
                final Dialog<DialogController> dialog = new Dialog<DialogController>("/fxml/DialogScenario.fxml", "#confirm");
                dialog.setTitle("Error!");
                dialog.getController().confirm.setText("OK");
                dialog.getController().message.setText(exception.getMessage());
                dialog.showAndWait();
            }
        });
        setOnSucceeded(new EventHandler<WorkerStateEvent>() {
            @Override
            public void handle(WorkerStateEvent workerStateEvent) {
                stopIndicator(indicator);
                process((T) workerStateEvent.getSource().getValue());
            }
        });

    }

    private static synchronized void startIndicator(ProgressIndicator indicator) {
        AtomicInteger count = indicatorMap.get(indicator);
        if(count == null){
            count = new AtomicInteger(0);
            indicatorMap.put(indicator, count);
        }
        count.incrementAndGet();
        indicator.setVisible(true);
    }

    private static synchronized void stopIndicator(ProgressIndicator indicator) {
        AtomicInteger count = indicatorMap.get(indicator);
        if(count == null){
            throw new IllegalStateException("Indicator wasn't started");
        }
        if(count.decrementAndGet() < 1){
            indicatorMap.remove(indicator);
            indicator.setVisible(false);
        }
    }

    protected abstract void process(T value);

    void execute(){
        new Thread(this).start();
    }
}

        
new BackgroundTask<Collection<Feature>>(progressIndicator){
            @Override
            protected Collection<Feature> call() throws Exception {
                //Удаленный вызов в фоновом потоке.
                return server.reloadFeatures();
            }

            @Override
            protected void process(Collection<Feature> f) {
                //Обновляем UI по завершению вызова
                configuration.updateFeatures(f);
            }
}.execute();