javafx button show onAction or lambda "->"

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package ingl.fx.button;

import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;

/**
*
* @author L
*/
public class PracticeButton extends Application {

@Override
public void start(Stage primaryStage) throws Exception {
//设置最大化高度 和 宽度
primaryStage.setMaxHeight(400);
primaryStage.setMaxWidth(400);
//设置最小化高度 和 宽度
primaryStage.setMinHeight(300);
primaryStage.setMinWidth(300);
//设置标题
primaryStage.setTitle("PracticeButton");
//创建一个窗体StackPane
StackPane pane = new StackPane();
//创建一个按钮
Button button = new Button("PracticeButton");
//设置按钮点击事件
button.setOnAction(ActionEvent -> {
System.out.print("hhhhhhhhhh");
});
//        button.setOnAction(new EventHandler<ActionEvent>(){
//            System.out.print("hhhhhhhhhh");
//        });
pane.getChildren().add(button);
//创建一个场景
Scene scene = new Scene(pane, 300, 250);
//设置一个场景
primaryStage.setScene(scene);

//显示窗体
primaryStage.show();
}

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