How do I convert my GUI java app to be an applet or display it on a webpage

Question

I have created a loan calculator program in netbeans, I got the application to run fine but now I want to add it into a html page.
I'm just looking for a place to start, I just don't know where to go from here, I want to know if I can actually convert my app with a few changes to an applet or if any one can point me to a forum of similar interest or tutorials that explain what I'm looking for.
I don't even know what i'm looking for except i want this program to run on a webpage.
Or is there a way to run my .jar file on a webpage??
My teacher has not taught us anything on this matter except the below code suggestions on converting and my program is more extensive than her examples for converting. This is what she briefly described on this subject.
1.To convert an application to an applet the main differences are: import java.awt.Graphics; import javax.swing.JApplet; import javax.swing.JOptionPane;
     Extend JApplet Replace main with public void init() method
Output with public void paint( Graphics g ) method
2. Remove calls to setSize, setTitle, pack, and any window listener calls, e.g., setDefaultCloseOperation. Compile the program---if something doesn't compile just comment it out for now.
3. Create a simple web page with the following body.
<applet CODE="__________.class" WIDTH="300" HEIGHT="300"
archive="http://www.cs.duke.edu/courses/fall01/cps108/resources/joggle.jar">
Your browser does not support applets </applet>
I understand those steps for a simple program like hello world but not my current app
Heres my code on the 2 extend off my first GUI of the Loan Application
public class AnalysisGUI extends GUI {
    /** Creates new form AnalysisGUI */
    public AnalysisGUI(java.awt.Frame parent, boolean modal) {
        super(parent, modal);
        initComponents();
    }//end constructor
    private DecimalFormat currency = new DecimalFormat("0.00");
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {
        analysisjButton = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        writejTextArea = new javax.swing.JTextArea();
        clearTextAreajButton = new javax.swing.JButton();
        setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
        analysisjButton.setText("Analysis");
        analysisjButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                analysisjButtonActionPerformed(evt);
        writejTextArea.setColumns(20);
        writejTextArea.setRows(5);
        jScrollPane1.setViewportView(writejTextArea);
        clearTextAreajButton.setText("Clear Analysis Output");
        clearTextAreajButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                clearTextAreajButtonActionPerformed(evt);
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(analysisjButton)
                    .addComponent(clearTextAreajButton))
                .addGap(18, 18, 18)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 433, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(86, 86, 86))
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap(306, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(analysisjButton)
                        .addGap(84, 84, 84)
                        .addComponent(clearTextAreajButton)
                        .addGap(113, 113, 113))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 263, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(22, 22, 22))))
        java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
        setBounds((screenSize.width-700)/2, (screenSize.height-627)/2, 700, 627);
    }// </editor-fold>
    private void analysisjButtonActionPerformed(java.awt.event.ActionEvent evt) {                                               
        // TODO add your handling code here:   
        //importing values for FOR loop of 13 pyaments a years
        ir13 = super.rate;
        balance13 = super.balance;
        time13 = super.time;
        payment13 = MortgageCalculator.CalculatePayment(ir13, balance13, time13, PayperYear13);           
        interest13 = round((balance13 * (ir13/PayperYear13)));                   
        principle13 = round(payment13 - interest13);
        //set up for 12 pyaments a year
        balance = super.balance;          
        ir = super.rate;
        time = super.time;         
        payment = super.payment;
        interest = round((balance * (ir/PayperYear12)));
        principle = round(payment - interest);
        //set up for 24 payments a year   
        balance24 = super.balance;          
        ir24 = super.rate;
        time24 = super.time;         
        payment24 = super.payment/2;
        interest24 = round((balance24 * (ir/PayperYear24)));
        principle24 = round(payment24 - interest24);
        //set up for 26 payemnts a years
        ir26 = super.rate;
        balance26 = super.balance;
        time26 = super.time;
        payment26 = MortgageCalculator.CalculatePayment(ir26, balance26, time26, PayperYear26);           
        interest26 = round((balance26 * (ir26/PayperYear26)));                   
        principle26 = round(payment26 - interest26);
     double totalPrinciple = 0;              //set to zero
     double totalInterest = 0;          //set to zero       
     for( int n = 0; n < time; n++)     //check Year of Loan
            totalPrinciple = 0;          //reset to zero for totaling Year n totals
            totalInterest = 0;          //reset to zero for totaling Year n totals
            writejTextArea.append("-----Based on 12 Payments Per Year-----\n");
            writejTextArea.append("          "+"          "+"Principle" + "    " +
                "Interest"+ "    "+
                "Balance"+"\n");            
            //loops through the monthly payments
            for(int i = 1; i <= PayperYear12; i++ )
            //Calculate applied amounts for chart to be printed
            interest = round((balance * ir)/PayperYear12);
            principle = round(payment - interest);
            balance = round(balance - principle);
            //total year end amounts
            totalPrinciple = totalPrinciple + principle;
            totalInterest = totalInterest + interest;
            writejTextArea.append("Payment " + i + " $" + currency.format(principle) + "     " +
                currency.format(interest) + "      $" +
                currency.format(balance)+"\n");     
            }//end for 12 payments per year
            //print 12 payments Totals          
            int yr = n + 1;
            writejTextArea.append("\n---Year " + yr + " Totals Based on 12 Payments Per Year---");
            writejTextArea.append("\nYear Total Principle: $" + currency.format(totalPrinciple));
            writejTextArea.append("\nYear Total Interest: $" + currency.format(totalInterest));
            writejTextArea.append("\nRemaining Balance: $" + currency.format(balance)+"\n");
            writejTextArea.append("\n-------------------------------------------------------\n");     
            //Start 13 PAYMENTS A YEAR TABLE
            double totalPrinciple13 = 0;          //reset to zero for totaling Year n totals
            double totalInterest13 = 0;          //reset to zero for totaling Year n totals
            writejTextArea.append("-----Based on 13 Payments Per Year-----\n");   
            writejTextArea.append("          "+"          "+"Principle" + "    " +
                "Interest"+ "    "+
                "Balance"+"\n");            
            //loops through the monthly 13 payments           
            for(int j = 1; j <= PayperYear13; j++ )
            //Calculate applied amounts for chart to be printed
            interest13 = round((balance13 * ir13)/PayperYear13);
            principle13 = round(payment13 - interest13);
            balance13 = round(balance13 - principle13);
            //total year end amounts
            totalPrinciple13 = totalPrinciple13 + principle13;
            totalInterest13 = totalInterest13 + interest13;
            //System.out.printf("\n%-10s %-10s %-10s %-10s %-10s", n + 1 , i + 1,Principle, Interest, Balance);
            //System.out.printf("\n%-10s %-10s %-10.2f %-10.2f %-10.2f", n + 1 , i + 1,round(principle), round(interest), balance);
            writejTextArea.append("Payment " + j + " $" + currency.format(principle13) + "     " +
                currency.format(interest13) + "      $" +
                currency.format(balance13)+"\n");         
            }//end for 13 payments per year
            //Print totals for 13 payments a year          
            yr = n + 1;
            writejTextArea.append("\n---Year " + yr + " Totals Based on 13 Payments Per Year---");
            writejTextArea.append("\nYear Total Principle: $" + currency.format(totalPrinciple13));
            writejTextArea.append("\nYear Total Interest: $" + currency.format(totalInterest13));
            writejTextArea.append("\nRemaining Balance: $" + currency.format(balance13)+"\n");
            writejTextArea.append("\n-------------------------------------------------------\n");             
            //Start 24 PAYMENTS A YEAR TABLE
            double totalPrinciple24 = 0;          //reset to zero for totaling Year n totals
            double totalInterest24 = 0;          //reset to zero for totaling Year n totals
            writejTextArea.append("-----Based on 24 Payments Per Year-----\n");
            writejTextArea.append("          "+"          "+"Principle" + "    " +
                "Interest"+ "    "+
                "Balance"+"\n");            
            //loops through the monthly payments
            for(int i = 1; i <= PayperYear24; i++ )
            //Calculate applied amounts for chart to be printed
            interest24 = round((balance24 * ir24)/PayperYear24);
            principle24 = round(payment24 - interest24);
            balance24 = round(balance24 - principle24);
            //total year end amounts
            totalPrinciple = totalPrinciple + principle24;
            totalInterest = totalInterest + interest24;
            writejTextArea.append("Payment " + i + " $" + currency.format(principle24) + "     " +
                currency.format(interest24) + "      $" +
                currency.format(balance24)+"\n"); 
            }//end for 24 payments per year
            //print 24 payments Totals
            yr = n +1;
            writejTextArea.append("\n---Year " + yr + " Totals Based on 24 Payments Per Year---");
            writejTextArea.append("\nYear Total Principle: $" + currency.format(totalPrinciple24));
            writejTextArea.append("\nYear Total Interest: $" + currency.format(totalInterest24));
            writejTextArea.append("\nRemaining Balance: $" + currency.format(balance24)+"\n");
            writejTextArea.append("\n-------------------------------------------------------\n");                        
            //Start 26 PAYMENTS A YEAR TABLE
            double totalPrinciple26 = 0;//reset to zero for totaling Year n totals
            double totalInterest26 = 0;     //reset to zero for totaling Year n totals
            writejTextArea.append("------Based on 26 Payments Per Year-----\n");
            writejTextArea.append("          "+"          "+"Principle" + "    " +
                "Interest"+ "    "+
                "Balance"+"\n");            
            //loops through the monthly payments 26 times
            for(int i = 1; i <= PayperYear26; i++ )
            //Calculate applied amounts for chart to be printed
            interest26 = round((balance26 * ir24)/PayperYear26);
            principle26 = round(payment26 - interest26);
            balance26 = round(balance26 - principle26);
            totalPrinciple = totalPrinciple + principle26;
            totalInterest = totalInterest + interest26;
            writejTextArea.append("Payment " + i + "  $" + currency.format(principle26) + "     " +
                currency.format(interest26) + "      $" +
                currency.format(balance26)+"\n");
            }//end for 26 payments per year           
            yr = n + 1;
            //prints 26 payments yearly totals
            writejTextArea.append("\n---Year " + yr + " Totals Based on 26 Payments Per Year---");
            writejTextArea.append("\nYear Total Principle: $" + currency.format(totalPrinciple26));
            writejTextArea.append("\nYear Total Interest: $" + currency.format(totalInterest26));
            writejTextArea.append("\nRemaining Balance: $" + currency.format(balance26)+"\n");
            writejTextArea.append("\n-------------------------------------------------------\n");                
        }//end for years of the loan
    private void clearTextAreajButtonActionPerformed(java.awt.event.ActionEvent evt) {
        // TODO add your handling code here:
        //clear analysis field
        writejTextArea.setText("");
    public static double round(double r)//round to cents method
          return Math.ceil(r*100)/100;
     }//end round  
    /**HI micha what a long progam
     * @param args the command line arguments
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                AnalysisGUI dialog = new AnalysisGUI(new javax.swing.JFrame(), true);
                dialog.addWindowListener(new java.awt.event.WindowAdapter() {
                    public void windowClosing(java.awt.event.WindowEvent e) {
                        System.exit(0);
                dialog.setVisible(true);
        });//end announymous
    }//end main mehtod
    //12 year declared varialbes
    //private double balance;   
    private double principle;
    private double ir;
    private double interest;
    private double PayperYear12 = 12;
    //Variables for 13 payments a years
    private int PayperYear13 = 13;
    private double balance13;
    private double principle13;
    private double ir13;
    private double interest13;
    private double payment13;
    private double time13;
    //Varialbes for 24 payments a year
    private int PayperYear24 = 24;
    private double balance24;
    private double principle24;
    private double ir24;
    private double interest24;
    private double payment24;
    private double time24;
    //Varialbes for 24 payments a year
    private int PayperYear26 = 26;
    private double balance26;
    private double principle26;
    private double ir26;
    private double interest26;
    private double payment26;
    private double time26;
    // Variables declaration - do not modify
    private javax.swing.JButton analysisjButton;
    private javax.swing.JButton clearTextAreajButton;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextArea writejTextArea;

Answer 1

Your original program extends "GUI" which appears to extend JFrame (correct me if I'm wrong). If so, the first thing you should do would be to re-write this so that it extends JPanel which shouldn't be that hard to do (at least it's not hard to do if you know a little Swing -- but I worry about someone coming into this from the netbeans-generated code world). Purists will tell you to not even extend this, to have your main GUI class hold an instance of JPanel instead, and this would work fine too, as long as one way or another, the main GUI program can produce your application displayed on a JPanel on demand.
If you've done this correctly, then using your JPanel in a JFrame is trivial: in a main method create a JFrame, and then simply add your JPanel to the JFrame's contentPane and display it. Likewise using your JPanel in a JApplet is just as trivial as you'd do essentially the same thing: add your JPanel to the JApplet's contentPane, but this time do it in the JApplet's init method.