I am working on a Java project where I am to create a Online

I am working on a Java project where I am to create a Online University Registration System, Currently I am having issues with my Login class checking the credentials and sending them to the appropriate second screen. What would I need to do to get this desired effect of logging in based on your credentials what I have currently provides a login screen and a set of credentials I am using as an example.

Credentials.Java

import java.util.ArrayList;

public class Credentials
{
   private ArrayList<String> validUsers;
   private ArrayList<String> validPasswords;
   // This is where users and passwords can be added
public void userList()
{
   validUsers = new ArrayList<String>();
   validPasswords = new ArrayList<String>();
  
   validUsers.add(\"student\");
   validUsers.add(\"professor\");
   validUsers.add(\"departmenthead\");
   validUsers.add(\"registration\");
  
   validPasswords.add(\"1111\");
   validPasswords.add(\"2222\");
   validPasswords.add(\"3333\");
   validPasswords.add(\"4444\");
}
public ArrayList<String> getValidUsers()
{
   return validUsers;
   }
public ArrayList<String> getValidPasswords()
{
   return validPasswords;
   }
}

Loginview.Java:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class LoginScreen {
   //needs to be an instance variable to interact with outside classes
       private JFrame loginFrame;
      
       BigSystem bsys;
      
       public void hideScreen() {
           loginFrame.setVisible(false);
       }
      
       public void showScreen() {
           loginFrame.setVisible(true);
       }
      
      
      
       /**
       * Constructs a telephone with a speaker, keypad, and microphone.
       */
       public LoginScreen(BigSystem b) {
           bsys = b;
           //JPanel is a generic lightweight container.
           //It will contain other components.
           JPanel mainPanel = new JPanel();
           mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
           mainPanel.add(new JLabel(\"Username:\"));
          
           JButton loginButton = new JButton(\"Login\");
           mainPanel.add(loginButton);
          
           loginButton.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent event) {
                   //set state 1 to show student screen
                   bsys.setState(1); //pass the key pressed as a String
               }
           });
          

          
           loginFrame = new JFrame();
           loginFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
           loginFrame.add(mainPanel);

           loginFrame.pack();
           //loginFrame.setVisible(true);
       }

}

Solution

Here is the code of NextPage.java

Here is the code of LoginDemo.java