Shaz Software Solutions

Loan Payment Calculator

Loan Repayment Calculator Desktop Application using Java GUI Swing

Class: LoanUI.java
Class: Loan.java
Class: FormatUI.java
Class: LoanMain.java
Author: Shahrzad Jahangirian
Language: Java (using Java 6) Download Java 6 and Download Java Runtime 6(JRE)
Date Added: Dec 24, 2013
Licence: All source codes are for showing my skills in Software Development to get me a Job as an Application Developer. You are not allowed to sell this Application or use my codes to develop an application for Sale or apply my codes to develop software for commercial use and profit. You can offer me a price to buy the Application for mass production or buy my codes to develop your application for profit. Also you may offer me a price to buy this Application for your Business and ask me to update the codes to match your Business Requirements.

Description: This is a Loan Repayment Calculator Application that I developed using Java programming language. User enters Loan Amount, Loan Term in years or months, Interest Rate, and the Start of repayment date and press Calculate button to get Monthly Repayment amount, Loan Pay Off Date, and Total Payments including Interest after end of Loan Term. I coded this Loan Repayment formula

How to Run: I tested all codes on Windows 7 Command Prompt with Java(TM) SE Runtime Environment 6 on my computer. ( you may download it by visiting this link )
You need to create all files and save it in a folder in your computer such as C:\javacodes and compile and run at command prompt as follows. I assumed you saved all files at C:\javacodes
C:\javacodes> javac FormatUI.java -d c:\javacodes "this statement compiles the class and save it in loanPKG package"
C:\javacodes> javac Loan.java -d c:\javacodes "this statement compiles the class and save it in loanPKG package"
C:\javacodes> javac LoanUI.java -d c:\javacodes "this statement compiles the class and save it in loanPKG package"
C:\javacodes> javac LoanMain.java "compiles the HealthMain class"
C:\javacodes> Java LoanMain"and this statement runs the Application"

Class: LoanUI.java

/*
Class: LoanUI
Author: Shahrzad Jahangirian
Date: Dec 24, 2013
Description: Gui or Graphical User Interface that Loan Application uses to get user input and display the result 
*/					
package loanPKG;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

//import loanPKG.Loan;

public class LoanUI
    extends JFrame {

private Loan loan = new Loan();
  private JPanel loanPanel = new JPanel();
  private JLabel loanAmountLabel = new JLabel();
  private JLabel loanTermLabel = new JLabel();
  private JLabel loanTermMonthLabel = new JLabel();
  private JLabel loanTermYearsLabel = new JLabel();
  private JLabel interestRateLabel = new JLabel();
  private JLabel interestRatePercentLabel = new JLabel();
  private JLabel dateLabel = new JLabel();
  private JLabel dayLabel = new JLabel();
  private JLabel monthLabel = new JLabel();
  private JLabel yearLabel = new JLabel();
  private JLabel monthlyPaymentLabel = new JLabel();
  private JLabel payOffDateLabel = new JLabel();
  private JLabel totalPaymentsLabel = new JLabel();
  private JLabel titleLabel = new JLabel();
  private JLabel statusBarLabel = new JLabel();
  private JTextField loanAmountTextField = new JTextField();
  private JTextField loanTermYearsTextField = new JTextField();
  private JTextField loanTermMonthTextField = new JTextField();
  private JTextField interestRateTextField = new JTextField();
  private JTextField monthlyPaymentTextField = new JTextField();
  private JComboBox yearComboBox = new JComboBox(loan.getYearString());
  private JComboBox dayComboBox = new JComboBox(loan.getDayString());
  private JComboBox monthComboBox = new JComboBox(loan.getMonthString());
  private JButton calculateButton = new JButton();
  private JButton clearButton = new JButton();
  private FormatUI format = new FormatUI();

public LoanUI() {
    try {
      jbInit();
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }

private void jbInit() throws Exception {
    formatUserInterfaces();

loanPanel.setBackground(new Color(236, 240, 242));
    loanPanel.setLayout(null);
    addToPanel();
    this.getContentPane().setBackground(new Color(236, 240, 242));
    this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    this.setResizable(true);
    this.setSize(400, 410);
    this.setResizable(false);
    this.getContentPane().setLayout(new BorderLayout());
    loanAmountTextField.addMouseListener(new
        LoanUI_loanAmountTextField_mouseAdapter(this));
    loanTermYearsTextField.addMouseListener(new
        LoanUI_loanTermYearsTextField_mouseAdapter(this));
    loanTermMonthTextField.addMouseListener(new
        LoanUI_loanTermMonthTextField_mouseAdapter(this));
    interestRateTextField.addMouseListener(new
        LoanUI_interestRateTextField_mouseAdapter(this));
    this.getContentPane().add(loanPanel, null);
    this.setTitle("Loan Calculator");
  }

public void addToPanel() {
    loanPanel.add(loanAmountLabel);
    loanPanel.add(loanTermLabel);
    loanPanel.add(loanTermMonthLabel);
    loanPanel.add(loanTermYearsLabel);
    loanPanel.add(interestRateLabel);
    loanPanel.add(interestRatePercentLabel);
    loanPanel.add(dateLabel);
    loanPanel.add(dayLabel);
    loanPanel.add(monthLabel);
    loanPanel.add(yearLabel);
    loanPanel.add(statusBarLabel);
    loanPanel.add(monthlyPaymentLabel);
    loanPanel.add(payOffDateLabel);
    loanPanel.add(totalPaymentsLabel);
    loanPanel.add(titleLabel);
    loanPanel.add(loanAmountTextField);
    loanPanel.add(loanTermYearsTextField);
    loanPanel.add(loanTermMonthTextField);
    loanPanel.add(interestRateTextField);
    loanPanel.add(monthlyPaymentTextField);
    loanPanel.add(yearComboBox);
    loanPanel.add(dayComboBox);
    loanPanel.add(monthComboBox);
    loanPanel.add(calculateButton);
    loanPanel.add(clearButton);

}

public void formatUserInterfaces() {
    titleLabel = format.formatLabel(titleLabel,
                                    "Loan Repayment Calculator", 15, 10,
                                    350, 35, 236, 240, 242, 60, 100, 129,
                                    "Arial", 0, 18, SwingConstants.CENTER,
                                    SwingConstants.LEFT);
    loanAmountLabel = format.formatLabel(loanAmountLabel, "Loan Amount  $", 15,
                                         50,
                                         150, 25, 236, 240, 242, 60, 100, 129,
                                         "Arial", 0, 12, SwingConstants.CENTER,
                                         SwingConstants.LEFT);
    loanAmountTextField = format.formatTextField(loanAmountTextField, "", 105,
                                                 50, 75, 20, 255, 255, 255, 60,
                                                 100, 129, "Arial", 0, 12);
    loanTermLabel = format.formatLabel(loanTermLabel, "Loan Term", 15, 75,
                                       150, 25, 236, 240, 242, 60, 100, 129,
                                       "Arial", 0, 12, SwingConstants.CENTER,
                                       SwingConstants.LEFT);
    loanTermYearsTextField = format.formatTextField(loanTermYearsTextField, "",
        105, 75, 75, 20, 255, 255, 255, 60, 100, 129, "Arial", 0, 12);
    loanTermYearsLabel = format.formatLabel(loanTermYearsLabel, "Years or", 190,
                                            75,
                                            50, 25, 236, 240, 242, 60, 100, 129,
                                            "Arial", 0, 12,
                                            SwingConstants.CENTER,
                                            SwingConstants.LEFT);

loanTermMonthTextField = format.formatTextField(loanTermMonthTextField, "",
        250, 75, 75, 20, 255, 255, 255, 60, 100, 129, "Arial", 0, 12);
    loanTermMonthLabel = format.formatLabel(loanTermMonthLabel, "Months", 335,
                                            75,
                                            50, 25, 236, 240, 242, 60, 100, 129,
                                            "Arial", 0, 12,
                                            SwingConstants.CENTER,
                                            SwingConstants.LEFT);
    interestRateLabel = format.formatLabel(interestRateLabel, "Interest Rate",
                                           15, 100,
                                           150, 25, 236, 240, 242, 60, 100, 129,
                                           "Arial", 0, 12,
                                           SwingConstants.CENTER,
                                           SwingConstants.LEFT);
    interestRateTextField = format.formatTextField(interestRateTextField, "",
        105, 100, 75, 20, 255, 255, 255, 60, 100, 129, "Arial", 0, 12);
    interestRatePercentLabel = format.formatLabel(interestRatePercentLabel,
                                                  "% per year", 190, 100,
                                                  85, 25, 236, 240, 242, 60,
                                                  100, 129,
                                                  "Arial", 0, 12,
                                                  SwingConstants.CENTER,
                                                  SwingConstants.LEFT);
    dateLabel = format.formatLabel(dateLabel, "Start Date", 15, 125,
                                   75, 25, 236, 240, 242, 60, 100, 129,
                                   "Arial", 0, 12, SwingConstants.CENTER,
                                   SwingConstants.LEFT);
    dayLabel = format.formatLabel(dayLabel, "Day", 105, 125,
                                  30, 25, 236, 240, 242, 60, 100, 129,
                                  "Arial", 0, 12, SwingConstants.CENTER,
                                  SwingConstants.LEFT);
    dayComboBox = format.formatComboBox(dayComboBox, 135, 125, 45, 20, false, false,
                                        0, 255, 255, 255, 60, 100, 129, "Arial",
                                        0, 10);
    monthLabel = format.formatLabel(monthLabel, "Month", 190, 125,
                                    40, 25, 236, 240, 242, 60, 100, 129,
                                    "Arial", 0, 12, SwingConstants.CENTER,
                                    SwingConstants.LEFT);
    monthComboBox = format.formatComboBox(monthComboBox, 230, 125, 45, 20, false, false,
                                          0, 255, 255, 255, 60, 100, 129,
                                          "Arial",
                                          0, 10);
    yearLabel = format.formatLabel(yearLabel, "Year", 285, 125,
                                   30, 25, 236, 240, 242, 60, 100, 129,
                                   "Arial", 0, 12, SwingConstants.CENTER,
                                   SwingConstants.LEFT);
    yearComboBox = format.formatComboBox(yearComboBox, 320, 125, 50, 20, false, false,
                                         0, 255, 255, 255, 60, 100, 129,
                                         "Arial",
                                         0, 10);
    calculateButton.setOpaque(true);
    calculateButton.setText("Calculate");
    calculateButton.addActionListener(new LoanUI_calculateButton_actionAdapter(this));
    calculateButton.setBounds(285, 165, 80, 25);
    calculateButton.setFont(new java.awt.Font("Arial", 0, 10));

clearButton.setOpaque(true);
    clearButton.setText("Clear");
    clearButton.addActionListener(new LoanUI_clearButton_actionAdapter(this));
    clearButton.setBounds(195, 165, 80, 25);
    clearButton.setFont(new java.awt.Font("Arial", 0, 10));

monthlyPaymentLabel = format.formatLabel(monthlyPaymentLabel,
                                             "",
                                             15, 205,
                                             350, 35, 236, 240, 242, 60, 100,
                                             129,
                                             "Arial", 0, 18,
                                             SwingConstants.CENTER,
                                             SwingConstants.LEFT);
    payOffDateLabel = format.formatLabel(payOffDateLabel,
                                         "",
                                         15, 245,
                                         350, 35, 236, 240, 242, 60, 100,
                                         129,
                                         "Arial", 0, 18,
                                         SwingConstants.CENTER,
                                         SwingConstants.LEFT);
    totalPaymentsLabel = format.formatLabel(totalPaymentsLabel,
                                            "",
                                            15, 285,
                                            350, 35, 236, 240, 242, 60, 100,
                                            129,
                                            "Arial", 0, 18,
                                            SwingConstants.CENTER,
                                            SwingConstants.LEFT);

statusBarLabel = format.formatLabel(statusBarLabel, " ", -3, 350,
                                        410, 25, 236, 240, 242, 60, 100, 129,
                                        "Arial", 0, 12, SwingConstants.CENTER,
                                        SwingConstants.LEFT);
    statusBarLabel.setBorder(BorderFactory.createLoweredBevelBorder());

}

public boolean validateEntries() {
    boolean valid = true;
    if ( (loanAmountTextField.getText().trim().equals("") == true) &&
        (loanTermYearsTextField.getText().trim().equals("") == true) &&
        (loanTermMonthTextField.getText().trim().equals("") == true) &&
        (interestRateTextField.getText().trim().equals("") == true)) {
      valid = false;
      statusBarLabel.setText(
          " Error: All fields must have values");
      loanAmountTextField.setBackground(new Color(250, 224, 235));
      loanTermYearsTextField.setBackground(new Color(250, 224, 235));
      loanTermMonthTextField.setBackground(new Color(250, 224, 235));
      interestRateTextField.setBackground(new Color(250, 224, 235));
    }
    if ( (loanAmountTextField.getText().trim().equals("0") == true) ||
      (loanTermYearsTextField.getText().trim().equals("0") == true) ||
      (loanTermMonthTextField.getText().trim().equals("0") == true)) {
    valid = false;
    statusBarLabel.setText(
        " Error: Loan Amount and Loan Term must have a value larger than 0");
    loanAmountTextField.setBackground(new Color(250, 224, 235));
    loanTermYearsTextField.setBackground(new Color(250, 224, 235));
    loanTermMonthTextField.setBackground(new Color(250, 224, 235));   
  }

if ( (loan.validateDouble(loanAmountTextField.getText().trim()) == false)
        || (loanAmountTextField.getText().trim().equals("") == true)) {
      valid = false;
      statusBarLabel.setText(
          " Error: Loan Amount must have an Amount Value (only numbers)");
      loanAmountTextField.setBackground(new Color(250, 224, 235));

}
    if ( (loanTermYearsTextField.getText().trim().equals("") == true) &&
        (loanTermMonthTextField.getText().trim().equals("") == true)) {
      valid = false;
      statusBarLabel.setText(
          " Error: Loan Term needs one value in Years or in Months");
      loanTermYearsTextField.setBackground(new Color(250, 224, 235));
      loanTermMonthTextField.setBackground(new Color(250, 224, 235));
    }
    else if ( (loanTermYearsTextField.getText().trim().equals("") == false) &&
             (loanTermMonthTextField.getText().trim().equals("") == false)) {
      valid = false;
      statusBarLabel.setText(
          " Error: Loan Term needs one value in Years or in Months");
      loanTermYearsTextField.setBackground(new Color(250, 224, 235));
      loanTermMonthTextField.setBackground(new Color(250, 224, 235));
    }
    else if ( (loanTermYearsTextField.getText().trim().equals("") == false) &&
             (loanTermMonthTextField.getText().trim().equals("") == true) &&
             (loan.validateDouble(loanTermYearsTextField.getText().trim()) == false)) {
      valid = false;
      statusBarLabel.setText(
          " Error: Loan Term in Years must be a number");
      loanTermYearsTextField.setBackground(new Color(250, 224, 235));

}
    else if ( (loanTermYearsTextField.getText().trim().equals("") == true) &&
             (loanTermMonthTextField.getText().trim().equals("") == false) &&
             (loan.validateDouble(loanTermMonthTextField.getText().trim()) == false)) {
      valid = false;
      statusBarLabel.setText(
          " Error: Loan Term in Months must be a number");
      loanTermYearsTextField.setBackground(new Color(250, 224, 235));

}
    if ( (loan.validateDouble(interestRateTextField.getText().trim()) == false)
        || (interestRateTextField.getText().trim().equals("") == true)) {
      valid = false;
      statusBarLabel.setText(
          " Error: Interest Rate must have a Value (only numbers)");
      interestRateTextField.setBackground(new Color(250, 224, 235));

}
    if (valid == true) {
      loanAmountTextField.setBackground(new Color(255, 255, 255));
      loanTermYearsTextField.setBackground(new Color(255, 255, 255));
      loanTermMonthTextField.setBackground(new Color(255, 255, 255));
      interestRateTextField.setBackground(new Color(255, 255, 255));

}
    return valid;
  }

public void calculateButton_actionPerformed(ActionEvent e) {
    monthlyPaymentLabel.setText("");
    payOffDateLabel.setText("");
    totalPaymentsLabel.setText("");
    if (validateEntries() == true) {
      assign();
      displayResult();
    }
  }

public void assign() {
    loan.setLoanAmount(loanAmountTextField.getText().trim());
    if (loanTermYearsTextField.getText().trim().equals("") == false) {
      loan.setLoanTermYears(loanTermYearsTextField.getText().trim());
      loan.setLoanTerm("Year");
    }
    else {
      loan.setLoanTermMonths(loanTermMonthTextField.getText().trim());
      loan.setLoanTerm("Month");
    }
    loan.setInterestRate(interestRateTextField.getText().trim());
    loan.setStartDay(dayComboBox.getSelectedItem().toString());
    loan.setStartMonth(monthComboBox.getSelectedIndex());
    loan.setStartYear(yearComboBox.getSelectedItem().toString());
  }

public void displayResult() {
    monthlyPaymentLabel.setText("Monthly Payment: $" +
                                loan.calculateMonthlyPayment());
    payOffDateLabel.setText("Pay Off Date       : " + loan.calculatePayOffDate());
    totalPaymentsLabel.setText("Total Payments  : $" +
                               loan.calculateTotalPayment());
  }

void clearButton_actionPerformed(ActionEvent e) {
    loanAmountTextField.setBackground(new Color(255, 255, 255));
    loanTermYearsTextField.setBackground(new Color(255, 255, 255));
    loanTermMonthTextField.setBackground(new Color(255, 255, 255));
    interestRateTextField.setBackground(new Color(255, 255, 255));
    loanAmountTextField.setText("");
    loanTermYearsTextField.setText("");
    loanTermMonthTextField.setText("");
    interestRateTextField.setText("");
    monthlyPaymentLabel.setText("");
    payOffDateLabel.setText("");
    totalPaymentsLabel.setText("");
  }

void loanAmountTextField_mouseEntered(MouseEvent e) {
    statusBarLabel.setText(" Enter a Loan Amount");
  }

void loanAmountTextField_mouseExited(MouseEvent e) {
    statusBarLabel.setText(" ");
  }

void loanTermYearsTextField_mouseExited(MouseEvent e) {
    statusBarLabel.setText(" ");
  }

void loanTermYearsTextField_mouseEntered(MouseEvent e) {
    statusBarLabel.setText(" Enter Loan Term in Years");
  }

void loanTermMonthTextField_mouseEntered(MouseEvent e) {
    statusBarLabel.setText(" Enter Loan Term in Month");
  }

void loanTermMonthTextField_mouseExited(MouseEvent e) {
    statusBarLabel.setText(" ");
  }

void interestRateTextField_mouseEntered(MouseEvent e) {
    statusBarLabel.setText(" Enter Loan Annual Interest Rate");
  }

void interestRateTextField_mouseExited(MouseEvent e) {
    statusBarLabel.setText(" ");
  }

}

class LoanUI_calculateButton_actionAdapter
    implements java.awt.event.ActionListener {
  LoanUI adaptee;

LoanUI_calculateButton_actionAdapter(LoanUI adaptee) {
    this.adaptee = adaptee;
  }

public void actionPerformed(ActionEvent e) {
    adaptee.calculateButton_actionPerformed(e);
  }
}

class LoanUI_clearButton_actionAdapter
    implements java.awt.event.ActionListener {
  LoanUI adaptee;

LoanUI_clearButton_actionAdapter(LoanUI adaptee) {
    this.adaptee = adaptee;
  }

public void actionPerformed(ActionEvent e) {
    adaptee.clearButton_actionPerformed(e);
  }
}

class LoanUI_loanAmountTextField_mouseAdapter
    extends java.awt.event.MouseAdapter {
  LoanUI adaptee;

LoanUI_loanAmountTextField_mouseAdapter(LoanUI adaptee) {
    this.adaptee = adaptee;
  }

public void mouseEntered(MouseEvent e) {
    adaptee.loanAmountTextField_mouseEntered(e);
  }

public void mouseExited(MouseEvent e) {
    adaptee.loanAmountTextField_mouseExited(e);
  }
}

class LoanUI_loanTermYearsTextField_mouseAdapter
    extends java.awt.event.MouseAdapter {
  LoanUI adaptee;

LoanUI_loanTermYearsTextField_mouseAdapter(LoanUI adaptee) {
    this.adaptee = adaptee;
  }

public void mouseExited(MouseEvent e) {
    adaptee.loanTermYearsTextField_mouseExited(e);
  }

public void mouseEntered(MouseEvent e) {
    adaptee.loanTermYearsTextField_mouseEntered(e);
  }
}

class LoanUI_loanTermMonthTextField_mouseAdapter
    extends java.awt.event.MouseAdapter {
  LoanUI adaptee;

LoanUI_loanTermMonthTextField_mouseAdapter(LoanUI adaptee) {
    this.adaptee = adaptee;
  }

public void mouseEntered(MouseEvent e) {
    adaptee.loanTermMonthTextField_mouseEntered(e);
  }

public void mouseExited(MouseEvent e) {
    adaptee.loanTermMonthTextField_mouseExited(e);
  }
}

class LoanUI_interestRateTextField_mouseAdapter
    extends java.awt.event.MouseAdapter {
  LoanUI adaptee;

LoanUI_interestRateTextField_mouseAdapter(LoanUI adaptee) {
    this.adaptee = adaptee;
  }

public void mouseEntered(MouseEvent e) {
    adaptee.interestRateTextField_mouseEntered(e);
  }

public void mouseExited(MouseEvent e) {
    adaptee.interestRateTextField_mouseExited(e);
  }
}

Class:Loan.java

/*
Class: Loan
Author: Shahrzad Jahangirian
Date: Dec 24, 2013
Description: A class to process common things about Loan and grouped them under 
 Loan class. It calculates Loan Monthly Repayment Amounts, Pay Off Date, and Total 
 Payments at end of Loan Term. 
*/

package loanPKG;

import java.util.*;
import java.text.*;

public class Loan {

private double loanAmount;
  private int loanTermYears;
  private int loanTermMonths;
  private double interestRate;
  private double monthlyPayment;
  private String loanTerm = new String();
  private int startDay;
  private int startMonth;
  private int startYear;
  private String payOffDate = new String();
  private int totalMonths;
  private Calendar startDate;
  private SimpleDateFormat sdf;
  private DecimalFormat df = new DecimalFormat("#.##");
  private String[] dayString = {
      "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14",
      "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26",
      "27", "28", "29", "30", "31"};
  private String[] monthString = {
      "Jan", "Fab", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct",
      "Nov", "Dec"};
  private String[] yearString = {
      "2000", "2001", "2002", "2003", "2004", "2005", "2006", "2007", "2008",
      "2009", "2010", "2011", "2012", "2013", "2014", "2015", "2016", "2017",
      "2018", "2019", "2020", "2021", "2022", "2023", "2024", "2025", "2026",
      "2027", "2028", "2029", "2030", "2031", "2032", "2033", "2034", "2035",
      "2036", "2037", "2038", "2039", "2040", "2041", "2042", "2043", "2044",
      "2045",
      "2046", "2047", "2048", "2049", "2050", "2051", "2052", "2053", "2054",
      "2055",
      "2056", "2057", "2058", "2059", "2060", "2061", "2062", "2063", "2064",
      "2065",
      "2066", "2067", "2068", "2069", "2070", "2071", "2072", "2073", "2074",
      "2075",
      "2076", "2077", "2078", "2079", "2080", "2081", "2082", "2083", "2084",
      "2085",
      "2086", "2087", "2088", "2089", "2090", "2091", "2092", "2093", "2094",
      "2095",
      "2096", "2097", "2098", "2099", "2100"};

public Loan() {

}

/* Method Name: calculateMonthlyPayment()
   to calculate monthly payment using Payment amount on a loan formula
                iA
   P = -----------------------
                     -N
              1-(1+i)
   */
  public String calculateMonthlyPayment() {

double monthlyInterestRate = (interestRate / 100) / 12;

if (loanTerm.equals("Year") == true) {
      totalMonths = loanTermYears * 12;
    }
    else {
      totalMonths = loanTermMonths;
    }
    if (monthlyInterestRate == 0) {
      monthlyPayment = loanAmount / totalMonths;
    }
    else {
      monthlyPayment = ( (monthlyInterestRate * loanAmount) /
                        (1 - Math.pow( (1 + monthlyInterestRate), -totalMonths)));
    }
    return String.valueOf(df.format(monthlyPayment));
  }

public String calculatePayOffDate() {

startDate = Calendar.getInstance();
    startDate.set(startYear, startMonth + 1, startDay);
    startDate.add(Calendar.MONTH, totalMonths - 2);
    sdf = new SimpleDateFormat("MMM, yyyy");
    payOffDate = sdf.format(startDate.getTime());
    return payOffDate;
  }

public String calculateTotalPayment() {
    double totalPayment = 0.0;
    totalPayment = monthlyPayment * totalMonths;
    return String.valueOf(df.format(totalPayment));
  }

public boolean validateDouble(String number) {
    boolean valid = true;
    double d = 0.0;
    try {
      d = Double.parseDouble(number);
    }
    catch (Exception ex) {
      valid = false;
    }
    return valid;
  }

public String[] getDayString() {
    return dayString;
  }

public String[] getMonthString() {
    return monthString;
  }

public String[] getYearString() {
    return yearString;
  }

public String getLoanAmount() {
    return String.valueOf(loanAmount);
  }

public String getLoanTermMonths() {
    return String.valueOf(loanTermMonths);
  }

public String getLoanTermYears() {
    return String.valueOf(loanTermYears);
  }

public String getInterestRate() {
    return String.valueOf(interestRate);
  }

public String getMonthlyPayment() {
    return String.valueOf(monthlyPayment);
  }

public void setLoanAmount(String loanAmount) {
    this.loanAmount = Double.parseDouble(loanAmount);
  }

public void setLoanTermYears(String loanTermYears) {
    this.loanTermYears = Integer.parseInt(loanTermYears);
  }

public void setLoanTermMonths(String loanTermMonths) {
    this.loanTermMonths = Integer.parseInt(loanTermMonths);
  }

public void setInterestRate(String interestRate) {
    this.interestRate = Double.parseDouble(interestRate);
  }

public void setMonthlyPayment(String monthlyPayment) {
    this.monthlyPayment = Double.parseDouble(monthlyPayment);
  }

public void setStartDay(String startDay) {
    this.startDay = Integer.parseInt(startDay);
  }

public void setStartMonth(int startMonth) {

this.startMonth = startMonth;
  }

public void setStartYear(String startYear) {
    this.startYear = Integer.parseInt(startYear);
  }

public void setLoanTerm(String loanTerm) {
    this.loanTerm = loanTerm;
  }

}

Class: FormatUI.java

/*
Class: FormatUI
Author: Shahrzad Jahangirian
Date: Dec 24, 2013
Description: A helper class that has been used by LoanUI to format different
Swing components.
*/
package loanPKG;

import javax.swing.*;
import java.awt.*;
import java.awt.*;
import javax.swing.*;
import java.lang.Exception;
import java.lang.*;

public class FormatUI {

public FormatUI() {

}

/* A method to return a formatted JLabel
   formatLabel(variable name,text,x-cordinate,y-cordinate,
     width,height,background Red RGB color,background Green RGB color,
   background Blue RGB color, foreground Red RGB color, foreground Green RGB color,
   foreground Blue RGB color, font face string,
   font style number(PLAIN, BOLD, ITALIC, or BOLD+ITALIC), font size.
   */
  public JLabel formatLabel(JLabel aLabel, String txt, int x, int y, int width,
                            int height, int Bred, int Bgreen, int Bblue,
                            int Fred, int Fgreen, int Fblue, String fontFace,
                            int fontStyle, int fontSize, int vert, int horz) {
    aLabel.setOpaque(true);
    aLabel.setText(txt);
    aLabel.setBounds(new Rectangle(x, y, width, height));
    aLabel.setBackground(new Color(Bred, Bgreen, Bblue));
    aLabel.setForeground(new Color(Fred, Fgreen, Fblue));
    aLabel.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    aLabel.setVerticalAlignment(vert);
    aLabel.setHorizontalAlignment(horz);

return aLabel;
  }

public JLabel formatLabel(JLabel aLabel, int x, int y, int width,
                            int height, int Bred, int Bgreen, int Bblue,
                            int Fred, int Fgreen, int Fblue, String fontFace,
                            int fontStyle, int fontSize, int vert, int horz) {
    aLabel.setOpaque(true);
    aLabel.setBounds(new Rectangle(x, y, width, height));
    aLabel.setBackground(new Color(Bred, Bgreen, Bblue));
    aLabel.setForeground(new Color(Fred, Fgreen, Fblue));
    aLabel.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    aLabel.setVerticalAlignment(vert);
    aLabel.setHorizontalAlignment(horz);

return aLabel;
  }

public JRadioButton formatRadioButton(JRadioButton aRadioButton, String txt, int x, int y, int width,
                           int height, int Bred, int Bgreen, int Bblue,
                           int Fred, int Fgreen, int Fblue, String fontFace,
                           int fontStyle, int fontSize) {
   aRadioButton.setOpaque(true);
   aRadioButton.setText(txt);
   aRadioButton.setBounds(new Rectangle(x, y, width, height));
   aRadioButton.setBackground(new Color(Bred, Bgreen, Bblue));
   aRadioButton.setForeground(new Color(Fred, Fgreen, Fblue));
   aRadioButton.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
   return aRadioButton;
 }

public JTextField formatTextField(JTextField aTextField, String txt, int x,
                                    int y, int width, int height, int Bred,
                                    int Bgreen,
                                    int Bblue, int Fred, int Fgreen, int Fblue,
                                    String fontFace, int fontStyle,
                                    int fontSize
                                    ) {
    aTextField.setBorder(BorderFactory.createCompoundBorder());
    aTextField.setOpaque(true);
    aTextField.setText(txt);
    aTextField.setBounds(new Rectangle(x, y, width, height));
    aTextField.setBackground(new Color(Bred, Bgreen, Bblue));
    aTextField.setForeground(new Color(Fred, Fgreen, Fblue));
    aTextField.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    return aTextField;
  }

public JFormattedTextField formatFormattedTextField(JFormattedTextField
      aFormattedTextField, int x, int y, int width, int height, String option,
      int Bred, int Bgreen,
      int Bblue, int Fred, int Fgreen, int Fblue, String fontFace,
      int fontStyle, int fontSize
      ) throws
      Exception {
    aFormattedTextField.setBorder(BorderFactory.createLoweredBevelBorder());
    aFormattedTextField.setOpaque(true);
    aFormattedTextField.setBounds(new Rectangle(x, y, width, height));
    aFormattedTextField.setBackground(new Color(Bred, Bgreen, Bblue));
    aFormattedTextField.setForeground(new Color(Fred, Fgreen, Fblue));
    aFormattedTextField.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    return aFormattedTextField;
  }

public JComboBox formatComboBox(JComboBox aComboBox, int x, int y, int width,
                                  int height, boolean editable,
                                  boolean selected,
                                  int index, int Bred, int Bgreen,
                                  int Bblue, int Fred, int Fgreen, int Fblue,
                                  String fontFace,
                                  int fontStyle, int fontSize
                                  ) {
    aComboBox.setBorder(BorderFactory.createCompoundBorder());
    aComboBox.setBounds(new Rectangle(x, y, width, height));
    aComboBox.setOpaque(true);
    aComboBox.setBackground(new Color(Bred, Bgreen, Bblue));
    aComboBox.setForeground(new Color(Fred, Fgreen, Fblue));
    aComboBox.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    aComboBox.setEditable(editable);
    if (selected == true) {
      aComboBox.setSelectedIndex(index);
    }
    return aComboBox;
  }

public JScrollPane formatScrollPane(JScrollPane aScrollpane, int x, int y,
                                      int width,
                                      int height, int Bred, int Bgreen,
                                      int Bblue, int Fred, int Fgreen,
                                      int Fblue, String fontFace,
                                      int fontStyle, int fontSize
                                      ) {
    aScrollpane.setBorder(BorderFactory.createLoweredBevelBorder());
    aScrollpane.setBounds(new Rectangle(x, y, width, height));
    aScrollpane.setBackground(new Color(Bred, Bgreen, Bblue));
    aScrollpane.setForeground(new Color(Fred, Fgreen, Fblue));
    aScrollpane.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    aScrollpane.setOpaque(true);

return aScrollpane;
  }

public JTextArea formatTextArea(JTextArea aTextArea, String txt, int x, int y,
                                  int width, int height, int Bred, int Bgreen,
                                  int Bblue, int Fred, int Fgreen,
                                  int Fblue, String fontFace, int fontStyle,
                                  int fontSize
                                  ) {
    aTextArea.setLineWrap(true);
    aTextArea.setWrapStyleWord(true);
    aTextArea.setEditable(true);
    aTextArea.setBounds(new Rectangle(x, y, width, height));
    aTextArea.setBackground(new Color(Bred, Bgreen, Bblue));
    aTextArea.setForeground(new Color(Fred, Fgreen, Fblue));
    aTextArea.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    aTextArea.setBorder(BorderFactory.createLoweredBevelBorder());
    return aTextArea;
  }

public TextArea formatTextArea(TextArea aTextArea, String txt, int x, int y,
                                 int width, int height, int Bred, int Bgreen,
                                 int Bblue, int Fred, int Fgreen,
                                 int Fblue, String fontFace, int fontStyle,
                                 int fontSize
                                 ) {
   aTextArea.setEditable(true);
   aTextArea.setBounds(new Rectangle(x, y, width, height));
   aTextArea.setBackground(new Color(Bred, Bgreen, Bblue));
   aTextArea.setForeground(new Color(Fred, Fgreen, Fblue));
   aTextArea.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
   return aTextArea;
 }

public JButton formatButton(JButton aButton, String txt, int x, int y,
                              int width,
                              int height, int Bred, int Bgreen,
                              int Bblue, int Fred, int Fgreen, int Fblue,
                              String fontFace,
                              int fontStyle, int fontSize
                              ) {
    aButton.setOpaque(true);
    aButton.setText(txt);
    aButton.setBounds(new Rectangle(x, y, width, height));
    aButton.setBackground(new Color(Bred, Bgreen, Bblue));
    aButton.setForeground(new Color(Fred, Fgreen, Fblue));
    aButton.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));

return aButton;
  }

public JCheckBox formatCheckBox(JCheckBox aButton, String txt, int x, int y,
                              int width,
                              int height, int Bred, int Bgreen,
                              int Bblue, int Fred, int Fgreen, int Fblue,
                              String fontFace,
                              int fontStyle, int fontSize
                              ) {
    aButton.setOpaque(true);
    aButton.setText(txt);
    aButton.setBounds(new Rectangle(x, y, width, height));
    aButton.setBackground(new Color(Bred, Bgreen, Bblue));
    aButton.setForeground(new Color(Fred, Fgreen, Fblue));
    aButton.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));

return aButton;
  }

public JPanel formatPanel(JPanel aPanel, int border, Color lineColor,
                            int lineThick,
                            String borderTitle, int x, int y, int width,
                            int height, int Bred, int Bgreen, int Bblue,
                            int Fred, int Fgreen, int Fblue, String fontFace,
                            int fontStyle, int fontSize) {
    aPanel.setOpaque(true);
    aPanel.setBounds(new Rectangle(x, y, width, height));
    aPanel.setBackground(new Color(Bred, Bgreen, Bblue));
    aPanel.setForeground(new Color(Fred, Fgreen, Fblue));
    aPanel.setFont(new java.awt.Font(fontFace, fontStyle, fontSize));
    switch (border) {
      case 0:
        aPanel.setBorder(BorderFactory.createLoweredBevelBorder());
        break;
      case 1:
        aPanel.setBorder(BorderFactory.createEmptyBorder());
        break;
      case 2:
        aPanel.setBorder(BorderFactory.createEtchedBorder());
        break;
      case 3:
        aPanel.setBorder(BorderFactory.createLineBorder(lineColor, lineThick));
        break;
      case 4:
        aPanel.setBorder(BorderFactory.createRaisedBevelBorder());
        break;
      case 5:
        aPanel.setBorder(BorderFactory.createTitledBorder(borderTitle));
        break;
    }
    return aPanel;
  }

}

Class:LoanMain.java