import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.stage.Stage;

public class TestComboBox extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception{

        int[] sizes = {5, 50, 150, 250, 500, 10000};
        ComboBox<String>[] cb = new ComboBox[sizes.length];
        HBox hBox = new HBox(20);
        for (int i = 0; i < sizes.length; i++) {
            cb[i] = new ComboBox<>();
            for (int j = 1 ; j <= sizes[i]; j++) {
                cb[i].getItems().add("Item " + j);
            }
            hBox.getChildren().add(cb[i]);

        }

        Scene scene = new Scene(hBox, 800, 200);
        primaryStage.setScene(scene);
        primaryStage.show();
    }


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