import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.DatePicker;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class SimpleDatePicker extends Application {

    @Override
    public void start(Stage primaryStage) {
        DatePicker datePicker = new DatePicker();
        VBox vbox = new VBox(datePicker);
        vbox.setStyle("-fx-alignment: center;");
        Scene scene = new Scene(vbox, 300, 200);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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