Hi everybody,

I'm working a program assignment for school. I thought my code was
good but it won't run. It compiles successfully but gives me this
error during runtime:

Exception in thread "main" java.lang.NoSuchMethodError

Do you have any advice? My code is below.

Thanks in advance,

Don

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/*
    Title: Mortgage Payment Calculator
    Programmer: Don
    Date: May 14, 2007
    Filename: MortPayCalc.java
    Purpose: This program calculates mortgage payment amounts.
*/

import java.text.DecimalFormat;
import javax.swing.JOptionPane;

class MortPayCalc2
{

    private boolean end = false;
    private DecimalFormat newFormat = new DecimalFormat ("$#,###.00");
    private double dPrincipal, dAPR, dPayment, dCurrMonthInterest,
dCurrMonthPrincipal, dLoanBalance;
    private double dLoanPrincipal = dPrincipal;
    private int iTerm, iPayments, iOption;
    private String Principal;
    private String Table = "";

    public void GetPrincipal()
    {

            Principal = JOptionPane.showInputDialog(null, "Enter Loan
Principal (ex. 20000): ", "Mortgage Payment
Calculator",JOptionPane.QUESTION_MESSAGE);
            dPrincipal = Double.parseDouble(Principal);

    }

    public void GetLoanTerms()
    {

        Object[] possibilities = {"Loan A", "Loan B", "Loan C"};
        String s = (String)JOptionPane.showInputDialog(null,"Please choose
your loan terms:\n",
       "Mortgage Payment
Calculator",JOptionPane.PLAIN_MESSAGE,null,possibilities,"Loan A");

        int [] Terms = {7, 15, 30};
        double [] Rates = {5.35, 5.5, 5.75};

        if (s == "Loan A")
            {
               iTerm = Terms[0];
               dAPR = Rates[0];
               }
        else if (s == "Loan B")
                {
               iTerm = Terms[1];
               dAPR = Rates[1];
               }
        else
                {
               iTerm = Terms[2];
               dAPR = Rates[2];
               }

    }

    public void CalculatePayment()
    {

        iPayments = iTerm * 12;
        dAPR = dAPR/100/12;
        dPayment = (dPrincipal*Math.pow((1+dAPR),iPayments)*dAPR)/
(Math.pow((1+dAPR),iPayments)-1);

    }

    public void CalculateAmortization()
    {

        for (int i = 0; i < iPayments; i++)
        {
            dCurrMonthInterest = dLoanPrincipal * dAPR;
            dCurrMonthPrincipal = dPayment - dCurrMonthInterest;
            dLoanBalance = dLoanPrincipal - dCurrMonthPrincipal;
            dLoanPrincipal = dLoanBalance;
            String Row = String.format(newFormat.format(dCurrMonthPrincipal) +
"  " + newFormat.format(dCurrMonthInterest) + "  " +
newFormat.format(dLoanBalance) + "\n");
            Table = Table + Row;
        }
    }

    public void DisplayResults()
    {

        iOption = JOptionPane.showConfirmDialog(null,
        "Loan Principal: " + newFormat.format(dPrincipal) + "\n" +
            "Loan Annual Percentage Rate: " + dAPR + "%" + "\n" +
            "Loan Term In Years: " + iTerm + " years" + "\n" +
            "Monthly Loan Payment Amount: " + newFormat.format(dPayment) +
"\n" +
        Table + "\n\n" +
            "Recalculate?",
           "Mortgage Payment Calculator", JOptionPane.YES_NO_OPTION);

    }

    public void main(String[] args)
    {

        while (end == false)
        {

            GetPrincipal();
            GetLoanTerms();
            CalculatePayment();
            CalculateAmortization();
            DisplayResults();

            if (iOption == JOptionPane.YES_OPTION)
                {
                     end = false;
                }
                else
                {
                     System.exit(0);
                }

        }

    }

}