Programming a simple slot machine game using Java

Posted by Brian Porter on August 22, 2014

Screen Shot 2014-08-22 at 17.48.55No matter how simple or complex the game is, Java can do the job!

On this post, let’s take a look at how beginners of Java programming can make a simple, yet fully functional slot machine. Slot machines have been around for a long time, but its entertainment value doesn’t seem to fade one bit. InterCasino, the first website to offer online casino gaming to the world in 1996, is still around and its slot games seem to get updated often. In addition, according to the American Gaming Association, slots generate around 62% – 90% of gaming money, making the machines the cash cows of casinos. With these facts in mind, don’t you ever want to create your very own slot machine that millions of casino gaming fans might like in the future? If you’re interested in creating Java-based slot games, the code below might prove useful for you.

package slotMachineGUI;

import java.awt.*;
import javax.swing.*;
import javax.swing.LayoutStyle.ComponentPlacement;
import java.text.DecimalFormat;
import java.util.Random;
import java.util.ArrayList;
import javax.swing.border.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class SlotMachineGUI {
    
    private JButton btnCash, btnSpin;
    private JCheckBox cbAlwaysWin, cbSuperJackpot, cbTrollface;
    private JFrame frmFrame;
    private JLabel lblCredits, lblLost, lblMatchThree, lblMatchTwo, lblMoney, lblReel1, lblReel2, lblReel3, lblStatus, lblWon;
    private JPanel pnlReels, pnlReel1, pnlReel2, pnlReel3;
    private JProgressBar prgbarCheatUnlocker;
    private JSeparator sepCheats, sepStats, sepStats2, sepStatus;
    private JToggleButton tgglSound;
    private int credits = 100, boughtCredits = 100, bet = 15, matchThree, matchTwo, win, lost;
    private double payout = 25.0, creditBuyout = 10.0, funds;
    private int reel1 = 7, reel2 = 7, reel3 = 7; // starting values of the reels.
    private ArrayList<ImageIcon> images = new ArrayList<ImageIcon>();
    private DecimalFormat df = new DecimalFormat("0.00");
    
    public SlotMachineGUI(int credits, int boughtCredits, int bet, double payout, double creditBuyout, int reel1, int reel2, int reel3) {
        this.credits=credits;
        this.boughtCredits=boughtCredits;
        this.bet=bet;
        this.payout=payout;
        this.creditBuyout=creditBuyout;
        this.reel1=reel1;
        this.reel2=reel2;
        this.reel3=reel3;
        createForm();
        loadImages();
        addFields();
        addButtons();
        layoutFrame();
        layoutReels();
        layoutOther();
    }
    
    public SlotMachineGUI() {
        createForm();
        loadImages();
        addFields();
        addButtons();
        layoutFrame();
        layoutReels();
        layoutOther();
    }
    
    /** Creates the JFrame and Panels. */
    private void createForm() {
        
        frmFrame = new JFrame();
        frmFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frmFrame.setTitle("Warner Slots");
        frmFrame.setResizable(false);
        frmFrame.setVisible(true);
        
        pnlReels = new JPanel();
        pnlReels.setBorder(BorderFactory.createEtchedBorder());
        
        pnlReel1 = new JPanel();
        pnlReel1.setBackground(new Color(255, 215, 0));
        pnlReel1.setBorder(new SoftBevelBorder(BevelBorder.LOWERED));
        pnlReel2 = new JPanel();
        pnlReel2.setBackground(new Color(255, 216, 0));
        pnlReel2.setBorder(new SoftBevelBorder(BevelBorder.LOWERED));
        pnlReel3 = new JPanel();
        pnlReel3.setBackground(new java.awt.Color(255, 215, 0));
        pnlReel3.setBorder(new SoftBevelBorder(BevelBorder.LOWERED));
        
    }
    
    /** Adds labels to the form. */
    private void addFields() {
        
        lblReel1 = new JLabel();
        lblReel2 = new JLabel();
        lblReel3 = new JLabel();
        
        sepStats = new JSeparator();
        lblMatchTwo = new JLabel();
        lblMatchTwo.setText("Matched Two: ");
        lblMatchThree = new JLabel();
        lblMatchThree.setText("Matched Three: ");
        lblWon = new JLabel();
        lblWon.setText("Won: ");
        
        sepStats2 = new JSeparator();
        sepStats2.setOrientation(SwingConstants.VERTICAL);
        lblCredits = new JLabel();
        lblCredits.setText("Credits: "+credits);
        lblMoney = new JLabel();
        lblMoney.setText("Money: £"+df.format(funds));
        lblLost = new JLabel();
        lblLost.setText("Lost: ");
        
        sepStatus = new JSeparator();
        lblStatus = new JLabel();
        lblStatus.setBackground(new Color(255, 255, 255));
        lblStatus.setFont(new Font("Arial", 1, 14));
        lblStatus.setHorizontalAlignment(SwingConstants.CENTER);
        lblStatus.setText("Welcome to WARNER SLOTS!!! ©2012");
        
        sepCheats = new JSeparator();
        prgbarCheatUnlocker = new JProgressBar();
        prgbarCheatUnlocker.setToolTipText("Fill the bar to unlock the cheat menu.");
        
        lblReel1.setIcon(images.get(reel1));
        lblReel2.setIcon(images.get(reel2));
        lblReel3.setIcon(images.get(reel3));
        
    }
    
    /** Adds buttons to the form. */
    private void addButtons() {
        
        btnSpin = new JButton();
        btnSpin.setBackground(new Color(50, 255, 50));
        btnSpin.setText("Spin");
        btnSpin.setToolTipText("Click to spin the reels!");
        btnSpin.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
        btnSpin.setInheritsPopupMenu(true);
        btnSpin.setMaximumSize(new Dimension(200, 50));
        btnSpin.setMinimumSize(new Dimension(200, 50));
        btnSpin.addActionListener(new SpinHandler());
        
        btnCash = new JButton();
        btnCash.setBackground(new Color(255, 0, 0));
        btnCash.setText("Buy Credits");
        btnCash.setToolTipText("£"+df.format(bet)+" converts to "+boughtCredits+" credits.");
        btnCash.setHorizontalTextPosition(SwingConstants.CENTER);
        btnCash.addActionListener(new BuyCreditsHandler());
        
        tgglSound = new JToggleButton();
        tgglSound.setSelected(false);
        tgglSound.setText("Sound ON");
        tgglSound.addActionListener(new SoundHandler());
        
        cbAlwaysWin = new JCheckBox();
        cbAlwaysWin.setText("Always Win Mode");
        cbAlwaysWin.setEnabled(false);
        cbAlwaysWin.addActionListener(new AlwaysWinHandler());
        
        cbTrollface = new JCheckBox();
        cbTrollface.setText("Trollface");
        cbTrollface.setEnabled(false);
        cbTrollface.addActionListener(new TrollfaceHandler());
        
        cbSuperJackpot = new JCheckBox();
        cbSuperJackpot.setText("Super Jackpot");
        cbSuperJackpot.setEnabled(false);
        cbSuperJackpot.addActionListener(new SuperPrizeHandler());
        
    }
    
    /** Lays out the frame. */
    private void layoutFrame() {
        
        GroupLayout frameLayout = new GroupLayout(frmFrame.getContentPane());
        frmFrame.getContentPane().setLayout(frameLayout);
        frameLayout.setHorizontalGroup(
        frameLayout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGap(0, 400, Short.MAX_VALUE)
        );
        frameLayout.setVerticalGroup(
        frameLayout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGap(0, 300, Short.MAX_VALUE)
        );
    }
    
    /** Lays out the panels and reels. */
    private void layoutReels() {
        
        GroupLayout pnlReelsLayout = new GroupLayout(pnlReels);
        pnlReels.setLayout(pnlReelsLayout);
        pnlReelsLayout.setHorizontalGroup(
        pnlReelsLayout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReelsLayout.createSequentialGroup()
        .addContainerGap()
        .addComponent(pnlReel1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
        .addGap(18, 18, 18)
        .addComponent(pnlReel2, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
        .addGap(18, 18, 18)
        .addComponent(pnlReel3, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        pnlReelsLayout.setVerticalGroup(
        pnlReelsLayout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReelsLayout.createSequentialGroup()
        .addContainerGap()
        .addGroup(pnlReelsLayout.createParallelGroup(GroupLayout.Alignment.TRAILING, false)
        .addComponent(pnlReel2, GroupLayout.Alignment.LEADING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(pnlReel1, GroupLayout.Alignment.LEADING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(pnlReel3, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        
        GroupLayout pnlReel1Layout = new GroupLayout(pnlReel1);
        pnlReel1.setLayout(pnlReel1Layout);
        pnlReel1Layout.setHorizontalGroup(
        pnlReel1Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReel1Layout.createSequentialGroup()
        .addContainerGap()
        .addComponent(lblReel1)
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        pnlReel1Layout.setVerticalGroup(
        pnlReel1Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReel1Layout.createSequentialGroup()
        .addContainerGap()
        .addComponent(lblReel1)
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        
        GroupLayout pnlReel2Layout = new GroupLayout(pnlReel2);
        pnlReel2.setLayout(pnlReel2Layout);
        pnlReel2Layout.setHorizontalGroup(
        pnlReel2Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReel2Layout.createSequentialGroup()
        .addContainerGap()
        .addComponent(lblReel2)
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        pnlReel2Layout.setVerticalGroup(
        pnlReel2Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReel2Layout.createSequentialGroup()
        .addContainerGap()
        .addComponent(lblReel2)
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        
        GroupLayout pnlReel3Layout = new GroupLayout(pnlReel3);
        pnlReel3.setLayout(pnlReel3Layout);
        pnlReel3Layout.setHorizontalGroup(
        pnlReel3Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReel3Layout.createSequentialGroup()
        .addContainerGap()
        .addComponent(lblReel3)
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        pnlReel3Layout.setVerticalGroup(
        pnlReel3Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(pnlReel3Layout.createSequentialGroup()
        .addContainerGap()
        .addComponent(lblReel3)
        .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        
    }
    
    /** lays out the remaining labels, check boxes, progress bars, etc. */
    private void layoutOther() {
        
        GroupLayout layout = new GroupLayout(frmFrame.getContentPane());
        frmFrame.getContentPane().setLayout(layout);
        
        layout.setHorizontalGroup(
        layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
        .addContainerGap()
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING, false)
        .addComponent(sepCheats)
        .addComponent(prgbarCheatUnlocker, GroupLayout.DEFAULT_SIZE, 426, Short.MAX_VALUE))
        .addGap(0, 0, Short.MAX_VALUE))
        .addGroup(layout.createSequentialGroup()
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING, false)
        .addGroup(layout.createSequentialGroup()
        .addComponent(cbAlwaysWin)
        .addGap(18, 18, 18)
        .addComponent(cbTrollface)
        .addGap(18, 18, 18)
        .addComponent(cbSuperJackpot)
        .addPreferredGap(ComponentPlacement.RELATED, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(tgglSound))
        .addComponent(btnSpin, GroupLayout.Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(pnlReels, GroupLayout.Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(sepStats, GroupLayout.Alignment.TRAILING)
        .addComponent(lblStatus, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addGroup(layout.createSequentialGroup()
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.TRAILING, false)
        .addComponent(lblMatchTwo, GroupLayout.Alignment.LEADING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(lblWon, GroupLayout.Alignment.LEADING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(lblMatchThree, GroupLayout.DEFAULT_SIZE, 149, Short.MAX_VALUE))
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addComponent(sepStats2, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING, false)
        .addComponent(lblLost, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(lblCredits, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(lblMoney, GroupLayout.DEFAULT_SIZE, 154, Short.MAX_VALUE))
        .addGap(0, 0, Short.MAX_VALUE)))
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.TRAILING)
        .addComponent(btnCash)
        .addComponent(sepStatus, GroupLayout.PREFERRED_SIZE, 426, GroupLayout.PREFERRED_SIZE)))
        .addContainerGap())))
        );
        
        layout.setVerticalGroup(
        layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
        .addContainerGap()
        .addComponent(pnlReels, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.RELATED)
        .addComponent(btnSpin, GroupLayout.PREFERRED_SIZE, 56, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addComponent(sepStats, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
        .addComponent(lblWon, GroupLayout.PREFERRED_SIZE, 19, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.RELATED)
        .addComponent(lblMatchTwo, GroupLayout.PREFERRED_SIZE, 19, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.RELATED)
        .addComponent(lblMatchThree, GroupLayout.DEFAULT_SIZE, 25, Short.MAX_VALUE))
        .addComponent(sepStats2)
        .addGroup(layout.createSequentialGroup()
        .addComponent(lblLost, GroupLayout.PREFERRED_SIZE, 19, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.RELATED)
        .addComponent(lblCredits, GroupLayout.PREFERRED_SIZE, 19, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.RELATED)
        .addComponent(lblMoney, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        .addComponent(btnCash, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addComponent(sepStatus, GroupLayout.PREFERRED_SIZE, 2, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addComponent(lblStatus, GroupLayout.PREFERRED_SIZE, 30, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addComponent(sepCheats, GroupLayout.PREFERRED_SIZE, 5, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.RELATED)
        .addComponent(prgbarCheatUnlocker, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
        .addPreferredGap(ComponentPlacement.UNRELATED)
        .addGroup(layout.createParallelGroup(GroupLayout.Alignment.BASELINE)
        .addComponent(cbAlwaysWin)
        .addComponent(cbTrollface)
        .addComponent(cbSuperJackpot)
        .addComponent(tgglSound))
        .addContainerGap())
        );
        
        frmFrame.pack();
        
    }
    
    /** Performs action when Buy Credits button is clicked. */
    class BuyCreditsHandler implements ActionListener {
        public void actionPerformed(ActionEvent event) {
            buyCredits();
        }
    }
    
    /** if the player has enough funds credits are added. */
    public void buyCredits() {
        if (funds >= creditBuyout) {
            funds -= creditBuyout;
            lblMoney.setText("Money: £"+df.format(funds));
            credits += boughtCredits;
            lblCredits.setText("Credits: "+credits);
            lblStatus.setText("+"+boughtCredits+" credits purchased! -£"+df.format(creditBuyout));
            } else {
            lblStatus.setText("Insufficient £ to purchase credits!");
        }
        buyCreditsCheck();
    }
    
    /** if user has enough funds to buy credits changes buttons colour to alert user. */
    public void buyCreditsCheck() {
        if (funds < bet) {
            btnCash.setBackground(new java.awt.Color(255, 0, 0));
            } else {
            btnCash.setBackground(new java.awt.Color(50, 255, 50));
        }
    }
    
    /** Performs action when Spin button is clicked. */
    class SpinHandler implements ActionListener {
        public void actionPerformed(ActionEvent event) {
            if (funds < creditBuyout && credits < bet) {
                lblStatus.setText("<html><a href='http://www.gambleaware.co.uk/'>www.gambleaware.co.uk</a></html>");
                } else if ((credits - bet) >= 0) {
                pnlReel1.setBackground(new java.awt.Color(255, 215, 0));
                pnlReel2.setBackground(new java.awt.Color(255, 215, 0));
                pnlReel3.setBackground(new java.awt.Color(255, 215, 0));
                genReelNumbers();
                matchCheck();
                } else {
                lblStatus.setText("Bet is "+bet+" credits, purchase more with £!");
            }
            buyCreditsCheck();
        }
    }
    
    /** Generates the 3 reel numbers. */
    public void genReelNumbers() {
        Random rand = new Random();
        if (cbAlwaysWin.isSelected() == true) { // If the Always win cheat mode is enabled.
            int winType = rand.nextInt(4); // generates number between 0-3 to determine the type of win
            reel1 = rand.nextInt(images.size());
            if (winType == 0) { // winType = 0 - Reels 1, 2 and 3 will all match.
                reel2 = reel1;
                reel3 = reel1;
                } else if (winType == 1) { // winType = 1 - Reels 1 and 2 will match.
                reel2 = reel1;
                } else if (winType == 2) { // winType = 2 - Reels 1 and 3 will match.
                reel3 = reel1;
                } else {    // winType = 3 - Reels 2 and 3 will match.
                if (reel1 >= 0 ) {
                    reel2 = reel1 + 1;
                    reel3 = reel1 + 1;
                    } if (reel1 == images.size()-1) {
                    reel2 = reel1 - 1;
                    reel3 = reel1 - 1;
                }
            }
            } else { // If the Always win cheat mode is disabled play a normal game.
            reel1 = rand.nextInt(images.size());
            reel2 = rand.nextInt(images.size());
            reel3 = rand.nextInt(images.size());
        }
        setReelIcon(reel1, reel2, reel3); // Set the reel image
    }
    
    /** Sets the reels icon based on loaded image in images ArrayList. */
    public void setReelIcon(int ico1, int ico2, int ico3) {
        lblReel1.setIcon(images.get(ico1)); // icon = the ArrayList index = random reel number
        lblReel2.setIcon(images.get(ico2));
        lblReel3.setIcon(images.get(ico3));
    }
    
    /** Checks for number matches and adjusts score depending on result. */
    public void matchCheck() {
        if (reel1 == reel2 && reel2 == reel3) {
            lblStatus.setText("You matched THREE symbols ("+images.get(reel1).getDescription()+")! +£"+df.format(getPrize(payout))+"!");
            lblMatchThree.setText("Matched Three: "+matchThree());
            pnlReel1.setBackground(new java.awt.Color(255, 0, 0)); // Highlights matched icons.
            pnlReel2.setBackground(new java.awt.Color(255, 0, 0));
            pnlReel3.setBackground(new java.awt.Color(255, 0, 0));
            } else if (reel1 == reel2 || reel1 == reel3) {
            lblStatus.setText("You matched TWO symbols ("+images.get(reel1).getDescription()+")! +£"+df.format(getPrize(payout))+"!");
            lblMatchTwo.setText("Matched Two: "+matchTwo());
            if (reel1 == reel2) {
                pnlReel1.setBackground(new java.awt.Color(255, 0, 0)); // Highlights matched icons.
                pnlReel2.setBackground(new java.awt.Color(255, 0, 0));
                } else if (reel1 == reel3){
                pnlReel1.setBackground(new java.awt.Color(255, 0, 0)); // Highlights matched icons.
                pnlReel3.setBackground(new java.awt.Color(255, 0, 0));
            }
            } else if (reel2 == reel3) {
            lblStatus.setText("You matched TWO symbols ("+images.get(reel2).getDescription()+")! +£"+df.format(getPrize(payout))+"!");
            lblMatchTwo.setText("Matched Two: "+matchTwo());
            pnlReel2.setBackground(new java.awt.Color(255, 0, 0)); // Highlights matched icons.
            pnlReel3.setBackground(new java.awt.Color(255, 0, 0));
            } else {
            lblStatus.setText("Sorry, you didn't match any symbols. -"+bet+" credits!");
            lblLost.setText("Lost: "+lose());
        }
        lblCredits.setText("Credits: "+(credits -= bet)); // deduct bet amount from available credits.
        lblMoney.setText("Money: £"+df.format((funds += getPrize(payout)))); // If there is a win add amount to cash pot.
        lblWon.setText("Wins: "+win()); // increment win amount.
    }
    
    /** sets progress bar equal to the current win count. if bar is full it unlocks cheat menu */
    public void prgBarCheck() {
        if (prgbarCheatUnlocker.getValue() <= 99) {
            prgbarCheatUnlocker.setValue(win);
            } else if (prgbarCheatUnlocker.getValue() == 100) { // after 100 wins unlock the cheats.
            prgbarCheatUnlocker.setValue(100);
            lblStatus.setText("100 wins! Congratulations you've unlocked the cheat menu!");
            cbTrollface.setEnabled(true);
            cbSuperJackpot.setEnabled(true);
            cbAlwaysWin.setEnabled(true);
        }
    }
    
    /** calculates prize to be awarded for win based on number of matches and cheats. */
    public double getPrize(double prize) {
        if (reel1 == reel2 && reel2 == reel3) {
            if (cbSuperJackpot.isSelected() == true) {
                prize *= 100; // if cheating and all are matched return the full pay out x100.
                } else {
                prize = payout; // if all are matched return the full pay out.
            }
            } else if (reel1 == reel2 || reel1 == reel3 || reel2 == reel3) {
            if (cbSuperJackpot.isSelected() == true) {
                prize *= 50; // if cheating and two are matched return the pay out x50.
                } else {
                prize = payout / 5; // if two are matched return 1/5th of the pay out.
            }
            } else {
            prize = 0; // If no win return no prize.
        }
        return prize;
    }
    
    /** Performs action when Super Jack pot check box is clicked. */
    class SuperPrizeHandler implements ActionListener{
        public void actionPerformed(ActionEvent e) {
            if (cbSuperJackpot.isSelected() == true) {
                lblStatus.setText("Super Prize mode ENABLED! The £ won is now x100!");
            }
            if (cbSuperJackpot.isSelected() == false) {
                lblStatus.setText("Super Prize mode DISABLED! :'(");
            }
        }
    }
    
    /** Performs action when Troll face check box is clicked. */
    class AlwaysWinHandler implements ActionListener{
        public void actionPerformed(ActionEvent e) {
            if (cbAlwaysWin.isSelected() == true) {
                lblStatus.setText("Always Win mode ENABLED! 7-7-7's here we come!");
            }
            if (cbAlwaysWin.isSelected() == false) {
                lblStatus.setText("Always Win mode DISABLED! :'(");
            }
        }
    }
    
    /** Performs action when Troll face check box is clicked. */
    class TrollfaceHandler implements ActionListener{
        public void actionPerformed(ActionEvent e) {
            if (cbTrollface.isSelected() == true && images.get(images.size()-1) != createImageIcon("images/Trollface.png", "Trollface")) {
                images.add(createImageIcon("images/Trollface.png", "Trollface")); // adds a bonus image to the images ArrayList.
                lblStatus.setText("Trollface mode ENABLED! Trolololololol!");
            }
            if (cbTrollface.isSelected() == false && images.get(images.size()-1) != createImageIcon("images/Trollface.png", "Trollface")) {
                images.remove(images.size()-1); // removes the bonus image (or last one added to the ArrayList) from the images ArrayList.
                lblStatus.setText("Trollface mode DISABLED! :'(");
            }
        }
    }
    
    /** Performs action when sound toggle button is clicked.
    * NOT IMPLEMENTED
    */
    class SoundHandler implements ActionListener{
        public void actionPerformed(ActionEvent e) {
            if (tgglSound.isSelected() == false) {
                tgglSound.setText("Sound ON");
                lblStatus.setText("Sound effects have been ENABLED!");
                // allowed to play sounds
                } else {
                tgglSound.setText("Sound OFF");
                lblStatus.setText("Sound effects have been DISABLED!");
                // disable sounds
            }
        }
    }
    
    /** Loads ImageIcons into the images ArrayList.
    *    The difficulty is determined by the number of images present in the ArrayList:
    *    •    Add images here to make game more difficult.
    *    •    Remove images here to make game easier.
    */
    public void loadImages() {
        images.add(createImageIcon("images/Banana.png", "Banana"));
        images.add(createImageIcon("images/Bar.png", "Bar"));
        images.add(createImageIcon("images/Bell.png", "Bell"));
        images.add(createImageIcon("images/Cherry.png", "Cherry"));
        images.add(createImageIcon("images/Clover.png", "Clover"));
        images.add(createImageIcon("images/Diamond.png", "Diamond"));
        images.add(createImageIcon("images/Plum.png", "Plum"));
        images.add(createImageIcon("images/Seven.png", "Seven"));
        images.add(createImageIcon("images/Watermelon.png", "Watermelon"));
    }
    
    /** Create a new ImageIcon, unless the URL is not found. */
    public ImageIcon createImageIcon(String path, String description) {
        java.net.URL imgURL = getClass().getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL, description);
            } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }
    
    /** Increments matchThree by 1 and returns value. */
    public int matchThree() {
        matchThree++;
        return matchThree;
    }
    
    /** Increments matchTwo by 1 and returns value. */
    public int matchTwo() {
        matchTwo++;
        return matchTwo;
    }
    
    /** Increments lost by 1 and returns value. */
    public int lose() {
        lost++;
        return lost;
    }
    
    /** Increments win by 1, increases progress bar and returns value. */
    public int win() {
        win = matchThree + matchTwo;
        prgBarCheck(); // Increments the progress bar to unlock cheat menu.
        return win;
    }
    
    public static void main(String args[]) {
        
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
            } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(SlotMachineGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
            } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(SlotMachineGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
            } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(SlotMachineGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
            } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(SlotMachineGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        
        java.awt.EventQueue.invokeLater(new Runnable() {
            
            public void run() {
                new SlotMachineGUI();
            }
        });
        
    }
    
}

Kudos to M ajestic, a YouTube user, for the code above. Here are the images that he used in the creation of the game.

If you made it this far, you may as well follow me on LinkedIn: Follow Brian Porter