public void mortCalc() {
		try {
			int j = 0;
			String temp = "";
			BufferedReader in = new BufferedReader(new FileReader("rate.txt"));
				while((temp = in.readLine()) != null) {
					rate[j] = Double.parseDouble(temp.trim());
					j++;
				}
			in.close();
		}
 
		catch (Exception E) {
		}

String temp = in.readLine();
while (temp != null) {
  // blah blah
  temp = readLine();
}

import java.awt.*;
 import javax.swing.*;
 import java.awt.event.*;
 import java.text.NumberFormat;
 import java.io.*;
 import java.lang.*;
 
 
 //sets up program variables
 public class MikesCalc extends JFrame implements ActionListener {
 	NumberFormat money = NumberFormat.getCurrencyInstance();
 	private JLabel title = new JLabel("Mortgage Calculator");
 	private JFrame amortFrame;
 	private JTextArea amort;
 	private String amortTable;
 	private JLabel prLabel = new JLabel("Loan Amount");
 	private JTextField pr = new JTextField(10);
	private JButton calcButton = new JButton("Calculate");
	private JLabel payLabel = new JLabel("Monthly Payment");
	private JTextField payment = new JTextField(10);
	private int years[] = {7, 15, 30};
	private double rate[] = new double[30];
	private double intRate, term, loanAmount, monthlyPayment, intPayment;
	private JLabel rateLabel = new JLabel("Annual Interest Rate: choose or enter one");
	private String [] rateChoice = new String[50];
	private JComboBox rateBox = new JComboBox();
	private JLabel yearsLabel = new JLabel("Loan Term (in years): choose or enter one");
	private String [] yearsChoice = {years[0] + "", years[1] + "", years[2] + ""};
	private JComboBox yearsBox = new JComboBox(yearsChoice);
	private String strRate[] = new String[50];
 
	//Creates the window
	public MikesCalc() {
		super("Mortgage Calculator");
		setSize(300, 200);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
 
		//Creates the container
		Container con = getContentPane();
		FlowLayout fresh = new FlowLayout(FlowLayout.LEFT);
		con.setLayout(fresh);
 
		//identifies the items that can trigger events
		calcButton.addActionListener(this);
		pr.addActionListener(this);
		yearsBox.addActionListener(this);
 
		//fills out the container
		con.add(prLabel);
		con.add(pr);
		con.add(rateLabel);
		con.add(rateBox);
		rateBox.setEditable(true);
		con.add(yearsLabel);
		con.add(yearsBox);
		yearsBox.setEditable(true);
		con.add(calcButton);
		con.add(payLabel);
		con.add(payment);
		payment.setEditable(false);
		setContentPane(con);
 
	}
 
	//Calls the calculations once the events are recognized
	public void actionPerformed(ActionEvent event) {
		Object source = event.getSource();
		if(source == calcButton) {
			mortCalc();
		}
	}
 
 
 
	//Does the calculations and exception handling
	public void mortCalc() {
 
 
 
		try {
			int j = 0;
			BufferedReader in = new BufferedReader(new FileReader("intrate.txt"));
			String temp = "";
 
				while((temp = in.readLine()) != null) {
					strRate[j] = temp;
					j++;
				}
 
			in.close();
		}
 
		catch (FileNotFoundException e) {
			System.out.println("Can't find file rate.txt!");
			return;
		}
 
		catch (IndexOutOfBoundsException e) {
			System.out.println("Too many numbers in data field");
			System.out.println("Processing aborted");
		}
 
		catch (IOException ioe) {
			System.out.println("IOException: " + ioe.getMessage());
		}
 
		rate[0] = Double.parseDouble(strRate[0]);
		rate[1] = Double.parseDouble(strRate[1]);
		rate[2] = Double.parseDouble(strRate[2]);
		rate[3] = Double.parseDouble(strRate[3]);
		rate[4] = Double.parseDouble(strRate[4]);
		rate[5] = Double.parseDouble(strRate[5]);
		rate[6] = Double.parseDouble(strRate[6]);
		String [] rateChoice = {rate[0] + "", rate[1] + "", rate[2] + "", rate[3] + "", rate[4] + "", rate[5] + "", rate[6] + ""};
		rateBox = new JComboBox(rateChoice);
		rateBox.addActionListener(new MikesCalc());
 
 
		try {
			double loanAmount = Double.parseDouble(pr.getText());
		}
 
		catch (NumberFormatException e) {
			JOptionPane.showMessageDialog(null, "Invalid Loan Amount entry, please enter a number", "Error", JOptionPane.PLAIN_MESSAGE);
			payment.setText(null);
			pr.setText(null);
 
		}
 
		try {
			double intRate = Double.parseDouble((String) rateBox.getSelectedItem());
		}
 
		catch (NumberFormatException e) {
			JOptionPane.showMessageDialog(null, "Invalid Interest Rate entry, please enter a percentage", "Error", JOptionPane.PLAIN_MESSAGE);
			payment.setText(null);
			pr.setText(null);
		}
 
		try {
			double term = Double.parseDouble((String) yearsBox.getSelectedItem());
		}
 
		catch (NumberFormatException e) {
			JOptionPane.showMessageDialog(null, "Invalid Term entry, please enter a number", "Error", JOptionPane.PLAIN_MESSAGE);
			payment.setText(null);
			pr.setText(null);
		}
 
 
		double loanAmount = Double.parseDouble(pr.getText());
		double intRate = Double.parseDouble((String) rateBox.getSelectedItem());
		double term = Double.parseDouble((String) yearsBox.getSelectedItem());
		double monthlyInt = (intRate / 100) / 12;
		double totalMonths = term * 12;
		double monthlyPayment = (loanAmount * monthlyInt)
                    / (1 - Math.pow(1/ (1 + monthlyInt), term * 12));
        String showPayment = money.format(monthlyPayment);
        payment.setText(showPayment);
 
 
		amortFrame = new JFrame();
		Container con = amortFrame.getContentPane();
		amort = new JTextArea("");
 
		amortTable = ("\tPrincipal Paid\t\tInterest Paid\t\tNew Balance\n");
		amort.append(amortTable);
		double intPayment = loanAmount * ((intRate / 100) / 12);
		term = term * 12;
				//starts amortization loop
				while (term > 0) {
 
					//performs the computations for the amortization
					double prPayment = monthlyPayment - intPayment;
					double bal = loanAmount - prPayment;
					amortTable = ("\t" + money.format(prPayment) + "\t\t" + money.format(intPayment) + "\t\t" + money.format(bal) + "\n");
					amort.append(amortTable);
					loanAmount = bal;
					intPayment = bal * ((intRate / 100) /12);
					term--;
				}
 
		//sets up amortization window
		amortFrame.setTitle("Mortgage Amortization");
		con.add(amort, BorderLayout.SOUTH);
		con.add(new JScrollPane(amort), BorderLayout.CENTER);
		amortFrame.setSize(600, 500);
		amortFrame.setVisible(true);
	}
 
	public static void main(String args[]) {
 
		MikesCalc app = new MikesCalc();
 
	}
}