java.lang.IncompatibleClassChangeError

[bigj]

public class PasswordField extends JFrame {

    private JPanel passwordPanel;

    private JPasswordField passwordField;

    private JLabel passwordLabel;

    private JButton userConfirmationBtn;
    private JButton submenu;
    
    private Image icon;
    
    private ImageIcon frameBackground;
    private ImageIcon buttonBackground;

    private String passwordAuthentication;
    
    public PasswordField() {

        initComponents();
    }

    private void initComponents() {

        icon = new ImageIcon("c:/pics/mercuryLogo.jpg").getImage().getScaledInstance(300, 300, 0);
        frameBackground = new ImageIcon("c:/pics/passwordbck2.jpg");
        buttonBackground = new ImageIcon("c:/pics/buttonbck");
        passwordField = new JPasswordField();
        passwordLabel = new JLabel("Password: ");
        userConfirmationBtn = new JButton("Enter");
        submenu = new JButton("Submenu");
        
        // set the properties of this label
        passwordLabel.setBounds(12, 13, 80, 20);
        passwordLabel.setFont(new Font("Monospaced", Font.BOLD, 12));
        passwordLabel.setForeground(Color.BLACK);

        
        // set the properties and actions of this text field
        passwordField.setBounds(88, 13, 185, 20);

        // set the properties and actions of this button
        Action pass = new AbstractAction() {

            public void actionPerformed(ActionEvent e) {

                Password p = new Password();

                p.addNewPassword("asd");
                // retrive the password data from the password field
                char[] passwordChars = passwordField.getPassword();

                String passwordStr = "";

                // convert the returned password characters as string
                for (int x = 0; x <= passwordChars.length - 1; x++) {

                    passwordStr = passwordStr + passwordChars[x];
                }
                // check if the password entered is valid
                
                if (p.isPasswordAuthentic(passwordStr)) {

                    new InventoryDatabase();
                    disableWindow();
                }
                else if (passwordStr.equals("")) {

                    PopUpDialog.popTheErrorMessage(" Unauthorized Entry", "Please Fill The Specified Field.");
                }
                else {

                    PopUpDialog.popTheErrorMessage(" Unauthorized Entry !", "Access Denied.");
                }
            }
        };
        userConfirmationBtn.addActionListener(pass);
        userConfirmationBtn.setMnemonic(KeyEvent.VK_E);
        userConfirmationBtn.setBounds(88, 55, 90, 20);
        userConfirmationBtn.setFont(new Font("Monospaced", Font.BOLD, 11));
        userConfirmationBtn.setBackground(Color.LIGHT_GRAY);
        userConfirmationBtn.registerKeyboardAction(userConfirmationBtn.getActionForKeyStroke(
                                                   KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, false)),
                                                   KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0, false),
                                                   JComponent.WHEN_IN_FOCUSED_WINDOW);
        userConfirmationBtn.registerKeyboardAction(userConfirmationBtn.getActionForKeyStroke(
                                                   KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, true)),
                                                   KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0, true),
                                                   JComponent.WHEN_IN_FOCUSED_WINDOW);

        // set the properties and actions of this button
        Action openSubmenu = new AbstractAction() {

            public void actionPerformed(ActionEvent e) {

                Submenu.openSubmenu();
            }
        };
        submenu.addActionListener(openSubmenu);
        submenu.setMnemonic(KeyEvent.VK_S);
        submenu.setBounds(184, 55, 90, 20);
        submenu.setFont(new Font("Monospaced", Font.BOLD, 11));
        submenu.setBackground(Color.LIGHT_GRAY);
        
        
        passwordPanel = new JPanel() {

            @Override
            protected void paintComponent(Graphics g) {

                // Scale image to size of component
                Dimension d = getSize();

                g.drawImage(frameBackground.getImage(), 0, 0, d.width, d.height, null);

                super.paintComponent(g);
            }
        };
        passwordPanel.setOpaque(false);

        // set this panel's layout to null for absolute positioning of
        // components
        passwordPanel.setLayout(null);
        
        // add the components to this panel
        passwordPanel.add(passwordLabel);
        passwordPanel.add(passwordField);
        passwordPanel.add(userConfirmationBtn);
        passwordPanel.add(submenu);

        // add the panel to the container
        getContentPane().add(passwordPanel);
        
        setTitle(" User Confirmation");
        setIconImage(icon);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(288, 120);
        setResizable(false);
        setLocationRelativeTo(null);
        setVisible(true);
    }

    /**
     * Invoke this method if this window doesnt have any more use for the current
     * event.
     */
    private void disableWindow() {

        setVisible(false);
    }
    
    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            
            public void run() {

                new PasswordField();
            }
        });
    }
}

Password class

public class Password {

    private static String[] passwords;

    public Password() {

        passwords = new String[] {"123", "ABC"};
    }

    public boolean isPasswordAuthentic(String password) {

        boolean isAuthentic = false;
        
        for (int x = 0; x <= passwords.length - 1; x++) {

            if (password.equals(passwords[x])) {

                isAuthentic = true;
                break;
            }
        }

        return isAuthentic;
    }

    public void addNewPassword(String newPassword) {

        // UNSUPPORTED
        throw new UnsupportedOperationException();
    }

    public void deletePassword(String password) {

        // UNSUPPORTED
        throw new UnsupportedOperationException();
    }
}

why does it throw me this?

Exception in thread "AWT-EventQueue-0" java.lang.IncompatibleClassChangeError: Expected static method xxTestxx.Password.addNewPassword(Ljava/lang/String;)V
        at xxTestxx.PasswordField$1.actionPerformed(PasswordField.java:83)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.plaf.basic.BasicButtonListener$Actions.actionPerformed(BasicButtonListener.java:287)
        at javax.swing.JComponent$ActionStandin.actionPerformed(JComponent.java:3368)
        at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1636)
        at javax.swing.JComponent.processKeyBinding(JComponent.java:2851)
        at javax.swing.KeyboardManager.fireBinding(KeyboardManager.java:267)
        at javax.swing.KeyboardManager.fireKeyboardAction(KeyboardManager.java:216)
        at javax.swing.JComponent.processKeyBindingsForAllComponents(JComponent.java:2928)
        at javax.swing.JComponent.processKeyBindings(JComponent.java:2920)
        at javax.swing.JComponent.processKeyEvent(JComponent.java:2814)
        at java.awt.Component.processEvent(Component.java:6040)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1848)
        at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:704)
        at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:969)
        at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:841)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:668)
        at java.awt.Component.dispatchEventImpl(Component.java:4502)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

when i change these two method's static declaration with every compile

    public void addNewPassword(String newPassword) {

        // UNSUPPORTED
        throw new UnsupportedOperationException();
    }

    public void deletePassword(String password) {

        // UNSUPPORTED
        throw new UnsupportedOperationException();
    }

i got those errors, but when i wait a few seconds and compile it again it produces my expected output

UnsupportedOperationException();

i cant figure how does this affect the changes that i made in my program..

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            
            public void run() {

                new PasswordField();
            }
        });
    }

should i always include this inner class when im updating or using any GUIs?
or should i always include this in all of my GUI classes?, because i have many classes that extends JFrame and JDialog with lots of components..

[hardwired]

    public void addNewPassword(String newPassword) {
        boolean unsupported = false;
        // You might be doing so checking in here
        // to determine whether or not this operation
        // is supported. If it isn't then you would
        // be interested in throwing an exception.
        // This next comment is suggesting this.
        // UNSUPPORTED
        if(unsupported)
            throw new UnsupportedOperationException();
    }

Otherwise, as soon as this method is called it throws an exception.

[sathishsengg]

I executed the code and i got ur expected Error. But i didnt get "java.lang.IncompatibleClassChangeError" . when this Error occured , whether fired "Enter Button" or "SubMenu" Button