Java Program to Calculate Remaining Balance on a Loan

Often, you will want to know the remaining balance on a loan. It is easily calculated if you know the original principal, the interest rate, the loan length, and the number of payments made. To find the remaining balance, you must sum the payments, subtracting from each payment the amount allocated to interest. Then subtract that result from the principal.

The RemBalance applet is used to find the remaining balance of a loan.

Java Program For Bank Loan:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
public class RemBalance extends JApplet
implements ActionListener {
JTextField orgPText, paymentText, remBalText,
rateText, numPayText;
JButton doIt;
double orgPrincipal;
double intRate;
double payment;
double numPayments;
final int payPerYear = 12;
NumberFormat nf;
public void init() {
try {
SwingUtilities.invokeAndWait(new Runnable () {
public void run() {
makeGUI();
}
});
} catch(Exception exc) {
System.out.println("Can't create because of "+ exc);
}
}
private void makeGUI() {
GridBagLayout gbag = new GridBagLayout();
GridBagConstraints gbc = new GridBagConstraints();
setLayout(gbag);
JLabel heading = new
JLabel("Find Loan Balance ");
JLabel orgPLab = new JLabel("Original Principal ");
JLabel paymentLab = new JLabel("Amount of Payment ");
JLabel numPayLab = new JLabel("Number of Payments Made ");
JLabel rateLab = new JLabel("Interest Rate ");
JLabel remBalLab = new JLabel("Remaining Balance ");
orgPText = new JTextField(10);
paymentText = new JTextField(10);
remBalText = new JTextField(10);
rateText = new JTextField(10);
numPayText = new JTextField(10);
remBalText.setEditable(false);
doIt = new JButton("Compute");
gbc.weighty = 1.0;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.anchor = GridBagConstraints.NORTH;
gbag.setConstraints(heading, gbc);
gbc.anchor = GridBagConstraints.EAST;
gbc.gridwidth = GridBagConstraints.RELATIVE;
gbag.setConstraints(orgPLab, gbc);
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbag.setConstraints(orgPText, gbc);
gbc.gridwidth = GridBagConstraints.RELATIVE;
gbag.setConstraints(paymentLab, gbc);
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbag.setConstraints(paymentText, gbc);
gbc.gridwidth = GridBagConstraints.RELATIVE;
gbag.setConstraints(rateLab, gbc);
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbag.setConstraints(rateText, gbc);
gbc.gridwidth = GridBagConstraints.RELATIVE;
gbag.setConstraints(numPayLab, gbc);
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbag.setConstraints(numPayText, gbc);
gbc.gridwidth = GridBagConstraints.RELATIVE;
gbag.setConstraints(remBalLab, gbc);
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbag.setConstraints(remBalText, gbc);
gbc.anchor = GridBagConstraints.CENTER;
gbag.setConstraints(doIt, gbc);
add(heading);
add(orgPLab);
add(orgPText);
add(paymentLab);
add(paymentText);
add(numPayLab);
add(numPayText);
add(rateLab);
add(rateText);
add(remBalLab);
add(remBalText);
add(doIt);
orgPText.addActionListener(this);
numPayText.addActionListener(this);
rateText.addActionListener(this);
paymentText.addActionListener(this);
doIt.addActionListener(this);
nf = NumberFormat.getInstance();
nf.setMinimumFractionDigits(2);
nf.setMaximumFractionDigits(2);
}
public void actionPerformed(ActionEvent ae) {
double result = 0.0;
String orgPStr = orgPText.getText();
String numPayStr = numPayText.getText();
String rateStr = rateText.getText();
String payStr = paymentText.getText();
try {
if(orgPStr.length() != 0 &&
numPayStr.length() != 0 &&
rateStr.length() != 0 &&
payStr.length() != 0) {
orgPrincipal = Double.parseDouble(orgPStr);
numPayments = Double.parseDouble(numPayStr);
intRate = Double.parseDouble(rateStr) / 100;
payment = Double.parseDouble(payStr);
result = compute();
remBalText.setText(nf.format(result));
}
showStatus("");
} catch (NumberFormatException exc) {
showStatus("Invalid Data");
remBalText.setText("");
}
}
double compute() {
double bal = orgPrincipal;
double rate = intRate / payPerYear;
for(int i = 0; i < numPayments; i++)
bal -= payment - (bal * rate);
return bal;
}
}

Output: