import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class Test extends Application {

	@Override
	public void start(Stage primaryStage) {
		VBox root = new VBox(createTreeView());
		Scene scene = new Scene(root, 300, 250);
		primaryStage.setTitle("TreeView Example");
		primaryStage.setScene(scene);
		primaryStage.show();
	}

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

	private TreeView createTreeView() {
		TreeItem<String> rootItem = new TreeItem<>("Root");
		TreeItem<String> item1 = new TreeItem<>("Item 1");
		TreeItem<String> item2 = new TreeItem<>("Item 2");
		TreeItem<String> item3 = new TreeItem<>("Item 3");
		TreeItem<String> item4 = new TreeItem<>("Item 1");
		item2.getChildren().add(item3);
		rootItem.getChildren().addAll(item1, item2, item4);

		TreeView<String> treeView = new TreeView<>(rootItem);
		rootItem.setExpanded(true);

		treeView.setShowRoot(false);
		treeView.setCellFactory(tv -> new TreeCell<String>() {
			@Override
			protected void updateItem(String item, boolean empty) {
				super.updateItem(item, empty);

				if (empty || item == null) {
					setText(null);
					setGraphic(null);
				} else {
					setText(item);
					setGraphic(new Label("W"));
				}
			}
		});
		return treeView;
	}
}