这个程序的addButton(String label,ActionListener listener);方法是怎么有错，请帮我改改！

Question

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;class CalculatorFrame extends JFrame
{
public CalculatorFrame()
{
setTitle("计算器");
CalculatorPanel panel=new CalculatorPanel();
add(panel);
pack();
}
}class CalculatorPanel extends JPanel
{
private JButton display;
private JPanel panel;
private double result;
private String lastCommand;
private boolean start;

public CalculatorPanel()
{
setLayout(new BorderLayout());//边界布局
result=0;
lastCommand="=";
start=true;
display=new JButton("0");
display.setEnabled(false);
add(display,BorderLayout.NORTH);

    InsertAction insert=new InsertAction();
    CommandAction command=new CommandAction();

panel=new JPanel();
panel.setLayout(new GridLayout(4,4));

addButton("7",insert);
addButton("8",insert);
addButton("9",insert);
addButton("/",command);

addButton("4",insert);
addButton("5",insert);
addButton("6",insert);
addButton("*",command);

addButton("1",insert);
addButton("2",insert);
addButton("3",insert);
addButton("-",command);

addButton("0",insert);
addButton(".",insert);
addButton("=",command);
addButton("+",command);

add(panel,BorderLayout.CENTER);
}

private void addButton(String label,ActionListener listener);
{
JButton button=new JButton("label"); //
button.addActionListener(listener);
panel.add(button);
}

private class InsertAction implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
String input=event.getActionCommand();

if(start)
{
display.setText("");
start=false;
}
display.setText(display.getText()+input);
}
}

private class CommandAction implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
String command=event.getActionCommand();

if(start)
{
if(command.equals("-"))
{
display.setText(command);
start=false;
}
else
lastCommand=command;
}
else
{
Calculate(Double.parseDouble(display.getText()));
lastCommand=command;
start=true;
}
}
}

public void Calculate(double x)
{
if(lastCommand.equals("+"))
result+=x;
else if(lastCommand.equals("-"))
result-=x;
else if(lastCommand.equals("*"))
result*=x;
else if(lastCommand.equals("/"))
result/=x;
else if(lastCommand.equals("="))
result=x;

display.setText(""+result);
}
}public class Calculator
{
public static void main(String[] args)
{
CalculatorFrame frame=new CalculatorFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
它为什么找不到符号呀，错在那里呢！

Answer 1

private void addButton(String label,ActionListener listener);
{
JButton button=new JButton("label"); //
button.addActionListener(listener);
panel.add(button);
}
多写了一个';'

Answer 2

private void addButton(String label,ActionListener listener)
{
JButton button=new JButton("label"); //应该是label
button.addActionListener(listener);
panel.add(button);
}