ComboBox() constructor from ComboBox has the following syntax.
public ComboBox()
In the following code shows how to use ComboBox.ComboBox() constructor.
import javafx.application.Application; import javafx.geometry.Insets; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.control.ComboBox; import javafx.scene.control.Label; import javafx.scene.layout.GridPane; import javafx.stage.Stage; /*from w w w .ja va2 s . c o m*/ public class Main extends Application { public static void main(String[] args) { launch(args); } @Override public void start(Stage stage) { Scene scene = new Scene(new Group(), 450, 250); ComboBox<String> emailComboBox = new ComboBox<String>(); emailComboBox.getItems().addAll("A","B","C","D","E"); emailComboBox.setValue("A"); System.out.println(emailComboBox.getValue()); 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); Group root = (Group) scene.getRoot(); root.getChildren().add(grid); stage.setScene(scene); stage.show(); } }