GUI problem

[nanna]

Hi,
I need your help in checking what is the error in this program?? When I try to run it error messages appear ??

import javax.swing.*;
import java.awt.event.*;
/**
  The RetailPriceWindow class displays a JFrame that lets a user enter
  a wholecost of an item and markup percentage of the item.When the calculate button is clicked, a dialog box is displayed with the item`s retail price.

  
*/

public class RetailPriceWindow extends JFrame {
    private JPanel panel;
    private JLabel costLabel;
    private JLabel markupLabel;
    private JTextField costeTextField;
    private JTextField markuptextField;
    private JButton calcButton;
    private final int WINDOW_WIDTH = 350;
    private final int WINDOW_HEIGHT = 200;

/**
constructor
*/

  public RetailPriceWindow() {
    setTitle("Item Retail Price");
    setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    buildPanel();
    add(panel);
    setVisible(true); }
  public static void main (String[] args) {
      new RetailPriceWindow();
  private void buildPanel() {
    panel = new JPanel();
    panel.add(costLabel);
    panel.add(markupLabel);
    panel.add(costTextField);
    panel.add(markupTextField);
    
    costLabel = new JLabel("Enter the item wholecost");
    markupLabel = new JLabel("Enter the item markup percentage");
    costTextField = new JTextField(10);
    markupTextField = new JTextField(10);
    calcButton = new JButton("Calculate");
    calcButton.addActionListener(new ButtonListener());
    panel.add(calcButton);
    
  private class ButtonListener implements ActionListener {
/**
  The actionperformed methods executes when the user clicks on the Calculate button.
  @param e The event object.
*/
   public void actionPerformed(ActionEvent e) {
      String input1;
      String input2;
      double retailprice;
      input = costTextField.getText();
      input = markupTextField.getText();
      retailprice = Double.parseDouble(input1)*(input2)/50;
   JOptionPane.showMessageDialog(null, "The retail price for" + "the item`s wholecost" +
               input1 + " and the item`s markup percentage" + input2 + " is" + retailprice);
     
    }      
   }
  }
 }
}

Run Test:
RetailPriceWindow.java:34: illegal start of expression
private void buildPanel() {
^
RetailPriceWindow.java:34: illegal start of expression
private void buildPanel() {
^
RetailPriceWindow.java:34: ';' expected
private void buildPanel() {
^
RetailPriceWindow.java:49: illegal start of expression
private class ButtonListener implements ActionListener
^
4 errors

[serjant]

you cannot declare method in the method.Look you declared the method in the main method.