java 程序出现标点错误 我是学java的新手 下面代码出现报错 请问是什么原因？如何解决？...

package exception;

import javax.swing.JButton;

import javax.swing.JPanel;

public class JpanelDemo {

public static void main (String[] args){

BaseFrame f = new BaseFrame("JPanel演示");

JPanel panel_1 = new JPanel();

JPanel panel_2 = new JPanel();

JButton button_1 = new JButton("按钮一");

JButton button_2 = new JButton("按钮二");

JButton button_3 = new JButton("按钮三");

panel_1.add(button_1);

panel_2.add(button_2);

panel_2.add(button_3);

f.add(panel_1);

f.add(panel_2);

f.showMe();

f.setVisible(true);

}

}