When a spinner is configured with e.g. integers (IntegerSpinnerValueFactory) and the user types in a String, e.g. 'abc' and focus another node, an exception is thrown (NumberFormatException).

The exception is thrown from a 'lost focus' event handler declared in the Spinner constructor and so cannot be caught by any obvious mechanism.

This is the same issue as JDK-8303478, which is for the DatePicker component.

In the example below, just type a String like 'abc' into the Spinner and click the Button next to it. You can see an exception in the console (NumberFormatException).

### SOURCE ###

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Spinner;
import javafx.scene.control.SpinnerValueFactory.IntegerSpinnerValueFactory;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class SpinnerBug extends Application {

    @Override
    public void start(final Stage primaryStage) throws Exception {
        Spinner<Integer> spinner = new Spinner<>(new IntegerSpinnerValueFactory(0, 10, 0));
        spinner.setEditable(true);

        Button button = new Button("Focus me");
        final Scene sc = new Scene(new HBox(spinner, button));
        primaryStage.setScene(sc);
        primaryStage.show();
    }

    public static void main(final String[] args) {
        Application.launch(args);
    }

}

### SOURCE END ###