Java ImageViewer - Simple. - Classes and Code Snippets

So, nothing special made it under my Java course time...

import javax.swing.*;

import java.awt.event.*;

import java.awt.*;

import java.awt.image.*;

import java.io.*;

import javax.imageio.*;

import java.net.*;

import static javax.swing.JOptionPane.*;

public class ImageViewer implements ActionListener	{

	private BufferedImage image;

	private JFrame frame;

	private String fileName;

	private JMenuItem menuItem[] = new JMenuItem[2];

	private JLabel area = new JLabel();

	private JScrollPane JSp = new JScrollPane(area,

			JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

	private JFileChooser dialog = new JFileChooser();


	public ImageViewer() {

		if (frame == null) {

			frame = new JFrame();

			JMenuBar menuBar = new JMenuBar();

            JMenu menu = new JMenu("File");

            frame.add(menuBar,BorderLayout.NORTH);

            frame.add(JSp);

            menuBar.add(menu);

            menuItem[0] = new JMenuItem("Open...");

            menuItem[1] = new JMenuItem("Exit");

            menuItem[0].addActionListener(this);

            menuItem[1].addActionListener(this);

            menuItem[1].setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Q,

            						 Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()));

            menuItem[0].setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,

                                     Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()));

            menu.add(menuItem[0]);

            menu.add(menuItem[1]);

            frame.setJMenuBar(menuBar);

            frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

            frame.setTitle(fileName);

            frame.setResizable(false);

            frame.pack();

            frame.setVisible(true);

		}

		frame.repaint();

	}

	public void readInFile(String fileName) {

		this.fileName = fileName;

		File file = new File(fileName);

		if(file.isFile()) {

            try {

				image = ImageIO.read(file);

			} catch (IOException e) {

				showMessageDialog(frame,"Does not compute !","No file read or found",INFORMATION_MESSAGE);

				e.printStackTrace();

			}

        }

		else {

            URL url = getClass().getResource(fileName);

            if (url == null) { 

            	try {

					url = new URL(fileName);

				} catch (MalformedURLException e) {

					showMessageDialog(frame,"Does not compute !","No Image file or found",INFORMATION_MESSAGE);

					e.printStackTrace();

				} 

            }

            try {

				image = ImageIO.read(url);

			} catch (IOException e) {

				showMessageDialog(frame,"Does not compute !","No Image file",WARNING_MESSAGE);

				e.printStackTrace();

			}

       }

}

	public void setImage(JLabel area){

		ImageIcon icon = new ImageIcon(image);

		area.setIcon(icon);

		frame.setSize(icon.getIconWidth(),icon.getIconHeight());

	}

	public void actionPerformed(ActionEvent e) {

		if(e.getSource()==menuItem[0]) {

			if(dialog.showOpenDialog(null)==(JFileChooser.APPROVE_OPTION)) {

					readInFile(dialog.getSelectedFile().getAbsolutePath());

				if(image==null) {

					showMessageDialog(frame,"Does not compute !","No Image file",INFORMATION_MESSAGE);

				}

				else {

					setImage(area);

				}

			}

		}

		else if(e.getSource()==menuItem[1]) {

			System.exit(0);

		}

	}

	public static void main(String[] arg) {

		new ImageViewer();

	}

}