Java Swing Applets in Mac Os

Question

hi there,
I am a student at the University of Portsmouth in the UK in my third and last year. I am doing my dissertation as a game using applets for a client at the university of which there consits four prototypes. One of the main specification points is that it should work on an apple mac, therefore I am using Swing applets. however with my first prototype it works fine on windows in windows Explorer, firefox and Netscape but i cant get it to work on Mac os 9 or X even with the latest version of java installed on the machine. Can anyone tell me why this is so, I would be very gratefull.
As I cant post the whole applet here as a file download I will just put some code snippets of the main program classes.
Applet ------------------------------
* Class JugglingBalls - A sub class of JApplet that combines the GameInterface and GamePanel into a single application
* @author (Liam Morren)
* @version (v1.0)
import java.awt.*;
import javax.swing.*;
public class JugglingBalls extends JApplet
    // instance variables -----------------------------------------------------------------------------------------------------------------------------------
    private GamePanel gamePanel; // The game panel including game and render loop
    private GameInterface gameInterface; // The swing interface to modify the game scene components
    // JApplet methods -------------------------------------------------------------------------------------------------------------------------------------
     * Called by the browser or applet viewer to inform this JApplet that it
     * has been loaded into the system. It is always called before the first
     * time that the start method is called.
    public void init()
        gamePanel = new GamePanel();
        gameInterface = new GameInterface(gamePanel.getGameScene());
        Container content = getContentPane(); // The container for components in the applet
        setLayout(new BoxLayout(content, BoxLayout.X_AXIS));
        content.add(gamePanel);
        content.add(gameInterface);
     * Returns information about this applet.
     * An applet should override this method to return a String containing
     * information about the author, version, and copyright of the JApplet.
     * @return a String representation of information about this JApplet
    public String getAppletInfo()
        // provide information about the applet
        return "Title: JugglingBalls  \nAuthor: Liam Morren  \nA simple application showing balls juggling in the air.";
Interface -------------------------------------
* Class GameInterface - Lets you manipulate the game components using swing components
* @author (Liam Morren)
* @version (v1.0)
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
public class GameInterface extends JPanel
    // instance variables -------------------------------------------------------------------------------------------------------------------------------------
    private GameScene gameScene; // Reference to the game scene
    private JTabbedPane gameTabs; // Tabs for Game, Balls and Background
    // Scene panel
    JButton pause, start, reset; // Buttons
    // Balls panel
    JRadioButton redBall, greenBall, blueBall, archBall, figureOfEightBall; // Radio buttons
    JCheckBox canSplit; // Check box
    JComboBox setAllPaths, setAllTypes, newBall, selectBall; // Drop down boxes
    JButton deleteBall; // Button
    Ball currentBall; // Current ball being changed
    // Background panel
    JRadioButton black, white, red, green, blue, hide, show, stop, move, arch, figureOfEight; // Radio buttons
    // Constructors -------------------------------------------------------------------------------------------------------------------------------------------
     * Constructor for objects of class GameInterface
    public GameInterface(GameScene gameSceneIn)
        gameScene = gameSceneIn; // Reference to the game scene
        gameTabs = new JTabbedPane(); // JTabbedPane to hold different toolbars
        gameTabs.setPreferredSize(new Dimension(200, 494)); // Set the preffered size for the tabbed pane
        currentBall = gameScene.getBall(0); // First ball
        // Add the panels to the tabbed pane
        gameTabs.addTab("Scene", makeScenePanel());
        gameTabs.addTab("Balls", makeBallsPanel());
        gameTabs.addTab("Background", makeBackgroundPanel());
        add(gameTabs); // Add the tab to the game interface panel
        setPreferredSize(new Dimension(200, 200));
    // Other methods ------------------------------------------------------------------------------------------------------------------------------------------
     * makeScenePanel
     * @return JPanel - The scene panel with buttons added
    private JPanel makeScenePanel()
        // Make scene panel
        JPanel scenePanel = new JPanel();
        scenePanel.setLayout(new BoxLayout(scenePanel, BoxLayout.Y_AXIS)); // Change layout
        pause = new JButton("Pause"); // Make buttons
        start = new JButton("Start");
        reset = new JButton("Reset");
        // Add button actions
        pause.addActionListener(new ActionListener() // Add button listener to pause button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                gameScene.setPaused(true); // Pause game
        start.addActionListener(new ActionListener() // Add button listener to start button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                gameScene.setPaused(false); // Unpause game
        reset.addActionListener(new ActionListener() // Add button listener to reset button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                gameScene.reset(); // Reset game
                updateSelectBallComboBox();
                changeSelectedBall(0);
        scenePanel.add(pause); // Add buttons to scene panel
        scenePanel.add(start);
        scenePanel.add(reset);
        return scenePanel;
     * makeBackgroundPanel
     * @return JPanel - The background panel with buttons added
    private JPanel makeBackgroundPanel()
        // Make scene panel
        JPanel backgroundPanel = new JPanel();
        backgroundPanel.setLayout(new GridLayout(5, 1, 2, 2)); // Change layout
        // Make buttons
        // background colour buttons
        JPanel backgroundcolour = new JPanel(); // Change backgroundcolour panel
        backgroundcolour.setBorder(BorderFactory.createLineBorder(Color.black));
        black = new JRadioButton("Black"); // Radio buttons to change colour
        white = new JRadioButton("white");
        black.setSelected(true); // Set black as already selected
        ButtonGroup backColourGroup = new ButtonGroup(); // Group buttons so only one can be pressed at a time
        backColourGroup.add(black); // Add buttons to group
        backColourGroup.add(white);
        backgroundcolour.setLayout(new GridLayout(2, 2, 0, 0)); // Change layout
        backgroundcolour.add(new JLabel("Background colour")); // Add label
        backgroundcolour.add(black); // Add buttons to colours panel
        backgroundcolour.add(white);
        // Add radio button actions
        black.addActionListener(new ActionListener() // Add button listener to black button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                gameScene.setBackgroundColour(false); // Background colour = black
        white.addActionListener(new ActionListener() // Add button listener to white button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                gameScene.setBackgroundColour(true); // Background colour = white
        // colour buttons
        JPanel colours = new JPanel(); // Change colours panel
        colours.setBorder(BorderFactory.createLineBorder(Color.black));
        red = new JRadioButton("Red"); // Radio buttons to change colour
        green = new JRadioButton("Green");
        green.setSelected(true); // Set green as already selected
        blue = new JRadioButton("Blue");
        ButtonGroup colourGroup = new ButtonGroup(); // Group buttons so only one can be pressed at a time
        colourGroup.add(red); // Add buttons to group
        colourGroup.add(green);
        colourGroup.add(blue);
        colours.setLayout(new GridLayout(2, 2, 0, 0)); // Change layout
        colours.add(new JLabel("Change colours")); // Add label
        colours.add(red); // Add buttons to colours panel
        colours.add(green);
        colours.add(blue);
        // Add radio button actions
        red.addActionListener(new ActionListener() // Add button listener to red button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                if (gameScene.getBackgroundEffect().getColour() != 0)
                    gameScene.getBackgroundEffect().setColour(0); // Background effect colour = red
        green.addActionListener(new ActionListener() // Add button listener to green button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                if (gameScene.getBackgroundEffect().getColour() != 1)
                    gameScene.getBackgroundEffect().setColour(1); // Background effect colour = green
        blue.addActionListener(new ActionListener() // Add button listener to blue button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                if (gameScene.getBackgroundEffect().getColour() != 2)
                    gameScene.getBackgroundEffect().setColour(2); // Background effect colour = blue
        // hide buttons
        JPanel hideShow = new JPanel(); // Change hideShow panel
        hideShow.setBorder(BorderFactory.createLineBorder(Color.black));
        hide = new JRadioButton("Hide"); // Radio buttons to hide show
        show = new JRadioButton("Show");
        show.setSelected(true); // Set show as already selected
        ButtonGroup hideShowGroup = new ButtonGroup(); // Group buttons so only one can be pressed at a time
        hideShowGroup.add(hide); // Add buttons to group
        hideShowGroup.add(show);
        hideShow.setLayout(new GridLayout(2, 2, 0, 0)); // Change layout
        hideShow.add(new JLabel("Hide / Show")); // Add label
        hideShow.add(hide); // Add buttons to hideShow panel
        hideShow.add(show);
        // Add radio button actions
        hide.addActionListener(new ActionListener() // Add button listener to hide button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    gameScene.getBackgroundEffect().hide(); // Hide
        show.addActionListener(new ActionListener() // Add button listener to show button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    gameScene.getBackgroundEffect().unHide(); // Unhide
        // stopMove buttons
        JPanel stopMove = new JPanel(); // Change StopMove panel
        stopMove.setBorder(BorderFactory.createLineBorder(Color.black));
        stop = new JRadioButton("Stop"); // Radio buttons to stop move
        move = new JRadioButton("Move");
        stop.setSelected(true); // Set stop as already selected
        ButtonGroup stopMoveGroup = new ButtonGroup(); // Group buttons so only one can be pressed at a time
        stopMoveGroup.add(stop); // Add buttons to group
        stopMoveGroup.add(move);
        stopMove.setLayout(new GridLayout(2, 2, 0, 0)); // Change layout
        stopMove.add(new JLabel("Stop / Move")); // Add label
        stopMove.add(stop); // Add buttons to stopMove panel
        stopMove.add(move);
        // Add radio button actions
        stop.addActionListener(new ActionListener() // Add button listener to stop button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    gameScene.getBackgroundEffect().setMove(false); // stop
        move.addActionListener(new ActionListener() // Add button listener to move button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    gameScene.getBackgroundEffect().setMove(true); // move
        // changePath buttons
        JPanel changePath = new JPanel(); // Change changePath panel
        changePath.setBorder(BorderFactory.createLineBorder(Color.black));
        arch = new JRadioButton("Arch"); // Radio buttons to change path
        figureOfEight = new JRadioButton("Figure of eight");
        arch.setSelected(true); // Set stop as already selected
        ButtonGroup changePathGroup = new ButtonGroup(); // Group buttons so only one can be pressed at a time
        changePathGroup.add(arch); // Add buttons to group
        changePathGroup.add(figureOfEight);
        changePath.setLayout(new GridLayout(2, 2, 0, 0)); // Change layout
        changePath.add(new JLabel("Change Path")); // Add label
        changePath.add(arch); // Add buttons to changePath panel
        changePath.add(figureOfEight);
        // Add radio button actions
        arch.addActionListener(new ActionListener() // Add button listener to arch button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    gameScene.getBackgroundEffect().setPath(new Arch()); // Arch
        figureOfEight.addActionListener(new ActionListener() // Add button listener to figureOfEight button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    gameScene.getBackgroundEffect().setPath(new FigureOfEight()); // Figure of eight
        // Add components to background panel
        backgroundPanel.add(backgroundcolour);
        backgroundPanel.add(colours);
        backgroundPanel.add(hideShow);
        backgroundPanel.add(stopMove);
        backgroundPanel.add(changePath);
        return backgroundPanel;
     * makeBallsPanel
     * @return JPanel - The ball panel with buttons added
    private JPanel makeBallsPanel()
        // Make balls panel
        JPanel ballsPanel = new JPanel();
        ballsPanel.setLayout(new BoxLayout(ballsPanel, BoxLayout.Y_AXIS)); // Change layout
        // Make buttons
        // set all drop down boxes
        JPanel setAll = new JPanel(); // Set all panel
        setAll.setBorder(BorderFactory.createLineBorder(Color.black));
        String[] setAllPathsChoices = {"Arch", "Figure of eight"}; // Selections for set all paths
        setAllPaths = new JComboBox(setAllPathsChoices); // Add selections to combo box
        String[] setAllTypesChoices = {"Primary ball", "Pastel ball", "3D ball", "Image ball"}; // Selections for set all types
        setAllTypes = new JComboBox(setAllTypesChoices); // Add selections to combo box
        setAll.add(new JLabel("Set all paths")); // Add combo boxes to set all panel
        setAll.add(setAllPaths);
        setAll.add(new JLabel("Set all types"));
        setAll.add(setAllTypes);
        // Add combo box actions
        setAllPaths.addActionListener(new ActionListener() // Add selection listener to set all paths combo box
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                if (setAllPaths.getSelectedItem() == "Arch")
                    gameScene.setAllPathsArch();
                else
                    gameScene.setAllPathsFigureOfEight();
        setAllTypes.addActionListener(new ActionListener() // Add selection listener to set all types combo box
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                if (setAllTypes.getSelectedItem() == "Primary ball")
                    gameScene.setAllTypesPrimaryBall();
                else if (setAllTypes.getSelectedItem() == "Pastel ball")
                    gameScene.setAllTypesPastelBall();
                else if (setAllTypes.getSelectedItem() == "Image ball")
                    gameScene.setAllTypesImageBall();
                else
                    gameScene.setAllTypesBall3D();
        // new ball drop down box
        JPanel newBallPanel = new JPanel(); // new ball panel
        newBallPanel.setBorder(BorderFactory.createLineBorder(Color.black));
        String[] newType = {"Primary ball", "Pastel ball", "3D ball", "Image ball"}; // Selections for new ball
        newBall = new JComboBox(newType); // Add selections to combo box
        newBallPanel.add(new JLabel("New ball")); // Add combo boxes to new ball panel
        newBallPanel.add(newBall);
        // Add combo box actions
        newBall.addActionListener(new ActionListener() // Add selection listener to newBall combo box
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                String ballType = (String) newBall.getSelectedItem();
                if (ballType == "Primary ball")
                    gameScene.addBall(new PrimaryBall(gameScene));
                else if (ballType == "Pastel ball")
                    gameScene.addBall(new PastelBall(gameScene));
                else if (ballType == "Image ball")
                    gameScene.addBall(new ImageBall(gameScene));
                else
                    gameScene.addBall(new Ball3D(gameScene));
                updateSelectBallComboBox();
                changeSelectedBall(gameScene.getBalls().size() - 1); // Update interface to show new ball
        // selected ball panel
        JPanel selectedBallPanel = new JPanel(); // selected ball panel
        selectedBallPanel.setBorder(BorderFactory.createLineBorder(Color.black));
        // Select ball
        selectBall = new JComboBox(gameScene.getBallList()); // Add ball list to the select drop down box
        deleteBall = new JButton("DeleteBall"); // Delete button
        // Ball colour
        redBall = new JRadioButton("Red"); // Red choice
        redBall.setSelected(true); // Start as selected
        greenBall = new JRadioButton("Green"); // Green choice
        blueBall = new JRadioButton("Blue"); // Blue choice
        ButtonGroup ballColour = new ButtonGroup(); // So only one colour can be selected at a tim
        ballColour.add(redBall);
        ballColour.add(greenBall);
        ballColour.add(blueBall);
        // Path
        archBall = new JRadioButton("Arch"); // Arch path choice
        archBall.setSelected(true); // Start as selected
        figureOfEightBall = new JRadioButton("Figure of eight"); // Figure of eight path choice
        ButtonGroup ballPath = new ButtonGroup(); // So only one path can be selected at a tim
        ballPath.add(archBall);
        ballPath.add(figureOfEightBall);       
        // Can split
        canSplit = new JCheckBox("Can split", false); // Initialy not selected
        selectedBallPanel.add(new JLabel("Select ball")); // Add components to selected ball panel
        selectedBallPanel.add(selectBall);
        selectedBallPanel.add(deleteBall);
        selectedBallPanel.add(new JLabel("Ball colour"));
        selectedBallPanel.add(redBall);
        selectedBallPanel.add(greenBall);
        selectedBallPanel.add(blueBall);
        selectedBallPanel.add(new JLabel("Path"));
        selectedBallPanel.add(archBall);
        selectedBallPanel.add(figureOfEightBall);
        selectedBallPanel.add(canSplit);
        // Add select ball drop down box action
        selectBall.addActionListener(new ActionListener() // Add selection listener to selectBall combo box
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                changeSelectedBall(selectBall.getSelectedIndex()); // Change the selected ball using the index from the select ball drop down box
        // Add delete button action
        deleteBall.addActionListener(new ActionListener() // Add selection listener to deleteBall button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                int tempIndex = selectBall.getSelectedIndex(); // Temp index
                if (gameScene.getBalls().size() > 1) // If there is more than 1 ball left
                    gameScene.removeBall(tempIndex); // Remove ball
                    updateSelectBallComboBox(); // Update with new ball list
                    changeSelectedBall(tempIndex - 1); // Update interface with new current selected ball
        // Add radio button colour actions
        redBall.addActionListener(new ActionListener() // Add button listener to redBall button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                if (currentBall.getColour() != 0)
                    currentBall.setColour(0); // currentBall colour = red
        greenBall.addActionListener(new ActionListener() // Add button listener to greenBall button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                if (currentBall.getColour() != 1)
                    currentBall.setColour(1); // currentBall colour = green
        blueBall.addActionListener(new ActionListener() // Add button listener to blueBall button
            public void actionPerformed(ActionEvent ev) // Background colour = blue
                if (currentBall.getColour() != 2)
                    currentBall.setColour(2); // currentBall colour = blue
        // Add path radio button actions
        archBall.addActionListener(new ActionListener() // Add button listener to arch button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    currentBall.setPath(new Arch()); // Arch
        figureOfEightBall.addActionListener(new ActionListener() // Add button listener to figureOfEight button
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    currentBall.setPath(new FigureOfEight()); // Figure of eight
        // Add can split check button actions
        canSplit.addActionListener(new ActionListener() // Add button listener to can split
            public void actionPerformed(ActionEvent ev) // Overide actionPerformed() method
                    currentBall.setCanGiveBirth(canSplit.isSelected()); // Ball can split if can split check button is selected
        // Add components to ball panel
        ballsPanel.add(setAll);
        ballsPanel.add(newBallPanel);
        ballsPanel.add(selectedBallPanel);
        return ballsPanel;
     * changeSelectedBall
     * @param  ballIndexIn - The numbered index of the ball in the game scene list of balls. If less than 0 then equals 0. If more than ball list size then equals last ball
    public void changeSelectedBall(int ballIndexIn)
        if (ballIndexIn < 0) // Make sure index is within bounds
            ballIndexIn = 0;
        else if (ballIndexIn >= gameScene.getBalls().size())
            ballIndexIn = gameScene.getBalls().size() - 1; // Else put within bounds at either end
        currentBall.highlight(false); // Unhighlight current ball
        currentBall = gameScene.getBall(ballIndexIn); // Get new current ball
        currentBall.highlight(true); // Highlight new current ball
        // Update controls to new ball
        selectBall.setSelectedIndex(ballIndexIn);
        switch (currentBall.getColour()) // Update colour controls
            case 0: redBall.setSelected(true); break;
            case 1: greenBall.setSelected(true); break;
            default: blueBall.setSelected(true); break;
        if (currentBall.getPath() instanceof Arch) // If path is arch
            archBall.setSelected(true); // Update controls as arch
        else
            figureOfEightBall.setSelected(true); // Else figure of eight
        canSplit.setSelected(currentBall.canGiveBirth()); // Set if the ball can split or not
     * updateSelectBallComboBox
     * This method updates the combo box selection model with a new one made from the updated balls arraylist from the game scene
    public void updateSelectBallComboBox()
        DefaultComboBoxModel model = new DefaultComboBoxModel(gameScene.getBallList());
        selectBall.setModel(model);
}Kind regards
Liam morren

Answer 1

http://docs.info.apple.com/article.html?artnum=301073
This link states Mac OS X 10.4 now supports Java 5.0. It does mention nothing about Mac OS 9 or previous version of OS X. The problem you may be facing is that your Mac is running only 1.4.2 or less. The class files compiled for Java 5.0 can't run in non 5.0 versions of the Java Virtual Machine. Java 5.0 was a major release for the Java language and thus the change in numbering (though it took a little bit for this to change).
Anyway you should confirm what version of Java you have installed on your Mac.
At a command prompt:
java -version
The above URL states that the previous 1.4.2 Java version is not uninstalled, and this could still be the preferred version to use for Java applications even after installing Java 5.0.
The URL above states there is a utility to set your apps to use Java 5.0 as the perferred Java version. Who knows maybe this is all you need to do. I hope this is the case, then it probably is an easy fix, otherwise you may need to rewrite your app in Java 1.4.2 to get it to run on your version of Mac.