default waarde combobox

Example 14-3 Creating Combo Boxes and Adding Them to the Scene

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;
 
public class ComboBoxSample extends Application {
    public static void main(String[] args) {
        launch(args);
    }
        
    final Button button = new Button ("Send");
    final Label notification = new Label ();
    final TextField subject = new TextField("");
    final TextArea text = new TextArea ("");
    
    String address = " ";
    
    @Override public void start(Stage stage) {
        stage.setTitle("ComboBoxSample");
        Scene scene = new Scene(new Group(), 450, 250);
        
        final ComboBox emailComboBox = new ComboBox();
        emailComboBox.getItems().addAll(
            "jacob.smith@example.com",
            "isabella.johnson@example.com",
            "ethan.williams@example.com",
            "emma.jones@example.com",
            "michael.brown@example.com"  
        );
        
        final ComboBox priorityComboBox = new ComboBox();
        priorityComboBox.getItems().addAll(
            "Highest",
            "High",
            "Normal",
            "Low",
            "Lowest" 
        );   

        priorityComboBox.setValue("Normal");
        
        GridPane grid = new GridPane();
        grid.setVgap(4);
        grid.setHgap(10);
        grid.setPadding(new Insets(5, 5, 5, 5));
        grid.add(new Label("To: "), 0, 0);
        grid.add(emailComboBox, 1, 0);
        grid.add(new Label("Priority: "), 2, 0);
        grid.add(priorityComboBox, 3, 0);
        grid.add(new Label("Subject: "), 0, 1);
        grid.add(subject, 1, 1, 3, 1);            
        grid.add(text, 0, 2, 4, 1);
        grid.add(button, 0, 3);
        grid.add (notification, 1, 3, 3, 1);
        
        Group root = (Group)scene.getRoot();
        root.getChildren().add(grid);
        stage.setScene(scene);
        stage.show();
    }    
}