jframe_problem

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JRootPane;
import javax.swing.JTextField;
import javax.swing.SwingConstants;


    public class Interface extends JFrame implements ActionListener {

            private Container contentPane;

            private JPanel buttonPanel, userPanel;

            private JButton loginButton, createUserButton, logoutButton, withdrawButton, depositButton, switchToRegisterButton, switchToLoginButton;

            private JLabel headerLabel, inputTopJTFLabel, inputPW1JPFLabel, toastLabel, inputPW2JPFLabel;

            public JTextField inputTopJTF;
            public JPasswordField inputPW1JPF, inputPW2JPF;

            JRootPane rootPane;

            public Interface(int width, int height, String title) {

                    //Setting up Interface
                    setTitle(title);
                    setSize(width, height);
                    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    setLocation(100,100);


                    Font header = new Font("TimesRoman", Font.PLAIN, 50);

                    ///////////////////////BUTTON PANEL///////////////////////

                    //Button Panel
                    buttonPanel = new JPanel();

                    //Buttons
                    //loginButton
                    loginButton = new JButton("Login");
                    loginButton.addActionListener(this);
                    loginButton.setAlignmentX(Component.CENTER_ALIGNMENT);

                    //switchToRegisterButton
                    switchToRegisterButton = new JButton("New User?");
                    switchToRegisterButton.addActionListener(this);
                    switchToRegisterButton.setAlignmentX(Component.CENTER_ALIGNMENT);

                    //switchToLoginButton
                    switchToLoginButton = new JButton("Switch to Login");
                    switchToLoginButton.addActionListener(this);
                    switchToLoginButton.setAlignmentX(Component.CENTER_ALIGNMENT);
                    switchToLoginButton.setVisible(false);

                    //createUserButton
                    createUserButton = new JButton("Register");
                    createUserButton.addActionListener(this);
                    createUserButton.setAlignmentX(Component.CENTER_ALIGNMENT);
                    createUserButton.setVisible(false);

                    //logoutButton
                    logoutButton = new JButton("Logout");
                    logoutButton.addActionListener(this);
                    logoutButton.setAlignmentX(Component.CENTER_ALIGNMENT);
                    logoutButton.setVisible(false);

                    //withdrawButton
                    withdrawButton = new JButton("Withdraw");
                    withdrawButton.addActionListener(this);
                    withdrawButton.setAlignmentX(Component.CENTER_ALIGNMENT);
                    withdrawButton.setVisible(false);

                    //depositButton
                    depositButton = new JButton("Deposit");
                    depositButton.addActionListener(this);
                    depositButton.setAlignmentX(Component.CENTER_ALIGNMENT);
                    depositButton.setVisible(false);

                    //Adding items to buttonPanel
                    buttonPanel.add(loginButton);
                    buttonPanel.add(switchToRegisterButton);
                    buttonPanel.add(switchToLoginButton);
                    buttonPanel.add(createUserButton);
                    buttonPanel.add(logoutButton);
                    buttonPanel.add(withdrawButton);
                    buttonPanel.add(depositButton);

                    ///////////////BODY PANEL//////////////////////

                    //Body Panel
                    userPanel = new JPanel();
                    userPanel.setLayout(new BoxLayout(userPanel, BoxLayout.PAGE_AXIS));

                    //JTextFields
                    //inputTopJTF
                    Dimension inputTopJTFDimension = new Dimension(100, 20);
                    inputTopJTF = new JTextField();
                    inputTopJTF.setMaximumSize(inputTopJTFDimension);

                    //inputPW1JPF
                    Dimension inputPW1JPFDimension = new Dimension(100, 20);
                    inputPW1JPF = new JPasswordField();
                    inputPW1JPF.setMaximumSize(inputPW1JPFDimension);

                    //inputPW2JPF
                    Dimension inputPW2JPFDimension = new Dimension(100, 20);
                    inputPW2JPF = new JPasswordField();
                    inputPW2JPF.setMaximumSize(inputPW2JPFDimension);
                    inputPW2JPF.setVisible(false);

                    //JLabels
                    //toastLabel
                    toastLabel = new JLabel("Please sign in or create new account.");
                    toastLabel.setAlignmentX(Component.CENTER_ALIGNMENT);

                    //inputTopJTFLabel
                    inputTopJTFLabel = new JLabel("Username:");
                    inputTopJTFLabel.setAlignmentX(Component.CENTER_ALIGNMENT);

                    //inputPW1JPFLabel
                    inputPW1JPFLabel = new JLabel("Password:");
                    inputPW1JPFLabel.setAlignmentX(Component.CENTER_ALIGNMENT);

                    //inputPW2JPFLabel
                    inputPW2JPFLabel = new JLabel("Confirm Password:");
                    inputPW2JPFLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
                    inputPW2JPFLabel.setVisible(false);

                    //Adding items to userPanel
                    userPanel.add(toastLabel);
                    userPanel.add(inputTopJTFLabel);
                    userPanel.add(inputTopJTF);
                    userPanel.add(inputPW1JPFLabel);
                    userPanel.add(inputPW1JPF);
                    userPanel.add(inputPW2JPFLabel);
                    userPanel.add(inputPW2JPF);

    ///////////////CONTENT PANE/////////////////////

            //Content Pane
            contentPane = getContentPane();

            //JLabels
            //headerLabel
            headerLabel = new JLabel("Bank", SwingConstants.CENTER);
            headerLabel.setFont(header);

            //PAGE_START
            contentPane.add(headerLabel, BorderLayout.PAGE_START);

            //LINE_START

            //CENTER
            contentPane.add(userPanel, BorderLayout.CENTER);

            //LINE_END

            //PAGE_END
            contentPane.add(buttonPanel, BorderLayout.PAGE_END);

        userPanel.setFocusable(true);
            userPanel.requestFocus();

            //Default Button
            rootPane = getRootPane();
            rootPane.setDefaultButton(loginButton);
            setVisible(true);

            }

    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println("hi");
    }

        public static void main(String[] args) {
            new Interface(500, 400, "hii");
        }
    }