javafx : TreeView with icon

1.Main.java

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Parent;
import javafx.scene.Scene;


public class Main extends Application {
	@Override
	public void start(Stage primaryStage) {
		try {
			Parent root = FXMLLoader.load(getClass().getResource("Main.fxml"));
			Scene scene = new Scene(root,300,300);
			scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
			primaryStage.setScene(scene);
			primaryStage.show();
		} catch(Exception e) {
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args) {
		launch(args);
	}
}

2.Main.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.TreeView?>
<?import javafx.scene.layout.AnchorPane?>


<AnchorPane prefHeight="300.0" prefWidth="300.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/9.0.1" fx:controller="application.MainController">
   <children>
      <TreeView fx:id="treeview" layoutX="50.0" layoutY="30.0" onContextMenuRequested="#mouseClick" onMouseClicked="#mouseClick" prefHeight="200.0" prefWidth="200.0" />
   </children>
</AnchorPane>

3.MainController.java

import java.net.URL;
import java.util.ResourceBundle;

import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TreeView;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;
import javafx.scene.control.TreeItem;

public class MainController implements Initializable{
	
	@FXML
	TreeView<String> treeview;
	
	Image icon = new Image(getClass().getResourceAsStream("/img/folder.png"));

	@Override
	public void initialize(URL arg0, ResourceBundle arg1) {
		TreeItem<String> root = new TreeItem<>("Root", new ImageView(icon));
		root.setExpanded(true);
		
		TreeItem<String> nodeA = new TreeItem<>("nodeA", new ImageView(icon));
		TreeItem<String> nodeB = new TreeItem<>("nodeB");
		TreeItem<String> nodeC = new TreeItem<>("nodeC");
		
		root.getChildren().addAll(nodeA,nodeB,nodeC);
		
		TreeItem<String> nodeA1 = new TreeItem<>("nodeA1");
		TreeItem<String> nodeB1 = new TreeItem<>("nodeB1");
		TreeItem<String> nodeC1 = new TreeItem<>("nodeC1");
		
		nodeA.getChildren().addAll(nodeA1,nodeB1,nodeC1);
		
		treeview.setRoot(root);
	}
	
	public void mouseClick(MouseEvent event) {
		if(event.getClickCount() == 2) {
			TreeItem<String> item = treeview.getSelectionModel().getSelectedItem();
			System.out.println(item.getValue());
		}
	}
}