Problem trying to get the program for my logon screen working

Question

hello.
i have developed a simple logon program. when i try to compile the program, i get 5 errors (errors + code are shown below). what in god's name are causing these errors and how can they be fixed?
thank you for your generous assistance.
----jGRASP exec: javac -g E:\CP4B Project\LogOn.java
LogOn.java:50: cannot find symbol
symbol: variable logOn
logOn = null;
^
LogOn.java:72: cannot find symbol
symbol : method setVisible(boolean)
location: class User
setVisible(false);
^
LogOn.java:83: cannot find symbol
symbol : method setVisible(boolean)
location: class User
setVisible(false);
^
LogOn.java:109: cannot find symbol
symbol : method setVisible(boolean)
location: class Administrator
setVisible(false);
^
LogOn.java:120: cannot find symbol
symbol : method setVisible(boolean)
location: class Administrator
setVisible(false);
^
5 errors
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LogOn extends JFrame{
   JTextField jtfUN = new JTextField(20);
   JPasswordField jtfPW = new JPasswordField(20);
   JButton jbOK = new JButton("OK");
   JButton jbCancel = new JButton("Cancel");
   public LogOn(){
      super("Welcome to Home Entertainment");
      setSize(250, 250);
      setDefaultCloseOperation(EXIT_ON_CLOSE);
      JPanel jp = new JPanel();
      JLabel unLabel = new JLabel("Username: ");
      JLabel pwLabel = new JLabel("Password: ");
      jp.add(unLabel);
      jp.add(jtfUN);
      jp.add(pwLabel);
      jp.add(jtfPW);
      jp.add(jbOK);
      jp.add(jbCancel);
      setContentPane(jp);
      pack();
      jbOK.addActionListener(new ActionListener(){
         public void actionPerformed(ActionEvent e){
            User u = new User();
            u.doLogOn();
            u.username = jtfUN.getText().trim();
            u.password = new String(jtfPW.getPassword());
            Administrator a = new Administrator();
            a.doLogOn();
            a.username = jtfUN.getText().trim();
            a.password = new String(jtfPW.getPassword());
      jbCancel.addActionListener(new ActionListener(){
         public void actionPerformed(ActionEvent e){
            logOn = null;
            setVisible(false);
   public static void main(String[] args){
      LogOn logOn = new LogOn();
class User{
   String username;
   String password;
   String[] userUsernameArray = {"Ann Smyth", "John Murphy"};
   String[] userPasswordArray = {"1", "2"};
   public void doLogOn(){
      int i, j;
      for(i = 0; i < userUsernameArray.length; i++){
         if(username.equals(userUsernameArray)){
setVisible(false);
//UserMainMenu umm = new UserMainMenu();
//umm.setVisible(true);
else{
JOptionPane.showMessageDialog(null, "Error\n\nYou have entered an incorrect username and/or password\nPlease try again", null, JOptionPane.ERROR_MESSAGE);
for(j = 0; j < userPasswordArray.length; j++){
if(password.equals(userPasswordArray[j])){
setVisible(false);
//UserMainMenu umm = new UserMainMenu();
//umm.setVisible(true);
else{
JOptionPane.showMessageDialog(null, "Error\n\nYou have entered an incorrect username and/or password\nPlease try again", null, JOptionPane.ERROR_MESSAGE);
class Administrator{
String username;
String password;
String[] adminUsernameArray = {"Administrator"};
String[] adminPasswordArray = {"0"};
public void doLogOn(){
int k, l;
String username;
String password;
String[] adminUsernameArray = {"Administrator"};
String[] adminPasswordArray = {"0"};
for(k = 0; k < adminUsernameArray.length; k++){
if(username.equals(adminUsernameArray[k])){
setVisible(false);
//AdminMainMenu amm = new AdminMainMenu();
//amm.setVisible(true);
else{
JOptionPane.showMessageDialog(null, "Error\n\nYou have entered an incorrect username and/or password\nPlease try again", null, JOptionPane.ERROR_MESSAGE);
for(l = 0; l < adminPasswordArray.length; l++){
if(password.equals(adminPasswordArray[l])){
setVisible(false);
//AdminMainMenu amm = new AdminMainMenu();
//amm.setVisible(true);
else{
JOptionPane.showMessageDialog(null, "Error\n\nYou have entered an incorrect username and/or password\nPlease try again", null, JOptionPane.ERROR_MESSAGE);

Answer 1

Pls. Post only once.
I think somebody already answered your problem in your other post.