Hello: I am stuck a bit on some code. I believe that I have the first class, the Date class, done correctly and I believe that I have most of the second class done correctly but am unsure of a part in the loan class requirements. Here is what the program should do:

Design a User-Defined class called Date.java with three attributes day, month and year. Implement an appropriate constructor, set and get methods getMonth(), setMonth(), getYear(), setYear(), getDay(), and setDay().


Next, design a User-Defined class called Loan.java, an object of which represents the real world Loan entity. Each loan object should store the following information:
a. Annual Interest Rate
b. Number of Years
c. Loan Amount
d. Loan Date (You would be specifying Loan Date of the type Date class you created earlier)

Here are the different operations that could be done on any Loan object.
a. Operation that returns the annual interest rate
b. Operation that returns the number of years
c. Operation that returns the loan amount
d. Operation that returns the Loan Date as a String value providing the date information.
e. Operation that sets a new annual interest rate
f. Operation that sets a new number of years
g. Operation that sets a new loan amount
h. Operation that calculates and returns the monthly payment
(Calculate the monthly payment using the following formulas:
o Monthly payment = (mIR * M) / (1 (1 / (1 + mIR)(12*nOY) ))
where:
o mIR = monthly interest rate (annual interest rate / 12)
o nOY = number of years
o M = Loan amount


i. Operation that calculates the total payment amount over the life of the loan
j. Operation that returns the overpayment amount


I am a bit unsure on part d on how to call the loan date from the date class and if I did the annual interest rate correctly. Thank you for the guidance. Here is the code that I have for the Date and Loan classes:

Code:
/**
 * This class holds the data for the day, month and year of a date
 * 
 * @author Ryan Moran 
 * @version 3/26/13
 */
public class Date
{
//declare instance variables

private int day;
private String month;
private int year;

//constructor
public Date ( int day, String month, int year )
{
this.day = day;
this.month = month;
this.year = year;
}

/** constructor:
 * sets initial values of instance variables
 */
public Date()
{
day = 0;
month = "unknown";
year = 0;
}
//method sets the day
public void setDay ( int day )
{
this.day = day;
}
//method sets the month
public void setMonth ( String month )
{
this.month = month;
}
//method sets the year
public void setYear ( int year )
{
this.year = year;
}
//method returns the day
public int getDay()
{
return day;
}
//method returns the month
public String getMonth()
{
return month;
}
//method returns the year
public int getYear()
{
return year;
}


}



/**
 * This class contains method for loan functions
 * 
 * @author Ryan Moran
 * @version 3/26/13
 */
public class Loan
{
   //declare variables
    private double annualInterestRate;
    private int numberOfYears;
    private double loanAmount;
    private String loanDate;
    
    //constructor
    public Loan ( double annualInterestRate, int numberOfYears, double loanAmount, String loanDate )
    {
        this.annualInterestRate = annualInterestRate;
        this.numberOfYears = numberOfYears;
        this.loanAmount = loanAmount;
        this.loanDate = loanDate;
    }
    
    /**constructor:
     * sets initial values of variables
     */   
    public Loan()
    {
        annualInterestRate = 0.0;
        numberOfYears = 0;
        loanAmount = 0.0;
        loanDate = "unknown";
    }
    
    //method sets the annual interest rate
    public void setAnnualInterestRate ( double annualInterestRate )
    {
        this.annualInterestRate = annualInterestRate;
    }
    //method sets the number of years
    public void setNumberOfYears ( int numberOfYears )
    {
        this.numberOfYears = numberOfYears;
    }
    //method sets the loan amount
    public void setLoanAmount ( double loanAmount )
    {
        this.loanAmount = loanAmount;
    }
    //method returns the annual interest rate
    public double getAnnualInterestRate()
    {
        return annualInterestRate;
    }
    //method returns the number of years
    public int getNumberOfYears()
    {
        return numberOfYears;
    }
    //method returns the loan amount
    public double getLoanAmount()
    {
        return loanAmount;
    }
    
}