import javafx.application.Application;
import javafx.stage.Stage;
import javafx.stage.FileChooser;
import java.io.File;

public class TestFileChooser extends Application {

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

    @Override
    public void start(Stage primaryStage) {
        FileChooser fc = new FileChooser();
        fc.getExtensionFilters().addAll(  
                new FileChooser.ExtensionFilter("Text Files (*.txt)", "*.txt"),
                new FileChooser.ExtensionFilter("Java Files (*.java)", "*.java"),
                new FileChooser.ExtensionFilter("All Files (*.*)", "*.*"));
        
        File fxmlFile = fc.showSaveDialog(primaryStage);
        
        primaryStage.show();
        primaryStage.hide();
        System.out.println("fxmlFile = " + fxmlFile);
    }
}