Creating an ArrayList as an attribute

Question

Hello all,
I'm new to Java and hope to learn a lot about the language. I've lost much sleep over this last program I was assigned to complete. I've tried everything to try and get this program working properly. As a school assignment we are required to create 3 classes: a loan class, a payment class and a class which handles database and query execution. All we have to do is print the loan information along with the payment information. A loan has multiple payments along with other attributes. I've written all of the code and am struggling on one area, the ArrayList portion of the program. We are supposed to have an ArrayList which contains information about loan payments (retrieved from the database). How do I create an instance of ArrayList <Payments> inside of my loan constructor? I keep getting a null pointer exception when running the program. Maybe my code makes more sense. Thanks in advance for any assistance.
import java.util.ArrayList;
public class Loan {
     private String loanID; //id no
     private String startDate; //date
     private double annualRate; //loan annual rate
     private double loanAmt; //loan amount due
     private int noYears; //years on loan
     private ArrayList<Payment> payments;
     /*public Loan (String l, String s, double ar, double la, int ny, ArrayList<Payment> p)
     { loanID = l;
          startDate = s;
          annualRate = ar;
          loanAmt = la;
          noYears = ny;
          ArrayList<Payment> payments = new ArrayList<Payment>();
     public Loan ()
          { this.loanID= loanID;
               this.startDate = startDate;
               this.annualRate= annualRate;
               this.loanAmt = loanAmt;
               this.noYears = noYears;
               this.payments = payments;
     }//end loan constructor
     public void setloanID (String l)
     loanID = l;
     }//end setloanID
     public String getloanID ()
          return loanID;
     }//end getloanID
     public void setstartDate (String s)
     startDate = s;
     }//end setstartDate
     public String getstartDate ()
          return startDate;
     }//end getstartDate
     public void setannualRate (double ar)
          annualRate = ar;
     public double getannualRate (double ar)
          return annualRate;
     }//end getstartDate
     public void setloanAmt (double la)
     loanAmt = la;
     public double getloanAmt (double la)
          return loanAmt;
     }//end getstartDate
     public void setnoYears (int ny)
          noYears = ny;
     public int getnoYears (int ny)
          return noYears;
     }//end getstartDate
     public ArrayList <Payment> getPayments ()
          return payments;
     }//end getPayments
}//end loan
import java.util.ArrayList;
public class Payment {
private String loanID;
private String datePaid;
private double amount;
private double principlePaid;
public Payment ()
     this.loanID = loanID;
     this.datePaid= datePaid;
     this.amount = amount;
     this.principlePaid = principlePaid;
}//end loan constructor
void setAmount (double amount){
     this.amount = amount;
public double getAmount()
     return amount;
void setdatePaid (String datePaid) {
     this.datePaid = datePaid;
public String getdatePaid (){
     return datePaid;
void setloanID (String loanID)
     this.loanID = loanID;
public String getloandID ()
     return loanID;
void setprinciplePaid (double principlePaid)
     this.principlePaid = principlePaid;
public double getprinciplePaid ()
     return principlePaid;
}//end payment class
import java.sql.*;
import java.util.ArrayList;
public class Hw6Dbase {
     //Driver NAme and Database URL
     static final String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
     static final String dbaseURL = "jdbc:odbc:homework5";
     //ArrayList<Payment> payments = new ArrayList<Payment>();
     public static void main (String args[])
          Loan loan = new Loan ("", "", 0, 0, 0, null); //ArrayList<Payment> p);
          Connection connection = null; //connection
     Statement statement = null; //queries
     try
     { Class.forName(driver);
     connection = DriverManager.getConnection(dbaseURL, " ", " ");
     statement = connection.createStatement();
     //query
     {ResultSet resultSet = statement.executeQuery("select * from loan where loanID= '0001'");
     //process the results
     //ResultSetMetaData dbMetaData = resultSet.getMetaData();
     //ResultSetMetaData dbMetaData2 = resultSet2.getMetaData();
     System.out.println("Loan Information");
          while (resultSet.next())
               loan.setloanID(resultSet.getString(1));
               loan.setstartDate(resultSet.getString(2));
               loan.setnoYears(resultSet.getInt(3));
               loan.setannualRate(Double.parseDouble(resultSet.getString(4)));
               loan.setloanAmt(Double.parseDouble(resultSet.getString(5)));
               String loanid = loan.getloanID();
               System.out.println ("Loan id:" + loanid);
          String loanDate = loan.getstartDate();
          double loanAmt = loan.getloanAmt(0.0);
          double rate = loan.getannualRate(0.0);
          int years = loan.getnoYears(0);
          //ArrayList <Payment> p = loan.getPayments();
          System.out.println("Start Date:" + loanDate);
          System.out.printf("Amount:%.2f\n", loanAmt);
          System.out.println("Annual Rate: "+ rate);
          System.out.println("Loan Duration:" + years);
          //System.out.println("TEST:" + p); //null
          }//end while
          System.out.println("\nPayments Received");
     ResultSet resultSet2 = statement.executeQuery("select * from payments where loan_ID='0001'");
          while (resultSet2.next())
               Payment payment = new Payment();
                    payment.setAmount(Double.parseDouble(resultSet2.getString(4)));
                    payment.setdatePaid(resultSet2.getString(3));
                    payment.setloanID(resultSet2.getString(2));
                    payment.setprinciplePaid(Double.parseDouble(resultSet2.getString(5)));
          //double amount = payment.getAmount();
                    //Test data
                    //String loanID = payment.getloandID();
                    //System.out.println("TEST:" + loanID);
                    //double pamount =payment.getAmount();
                    loan.getPayments().add(payment);
          //loan.payments.add(payment);
                    int n = loan.getPayments().size();
                    for (int i= 1; i<= n; i++)
                    //System.out.println(i);
                         System.out.println (loan.getPayments().get(i).getAmount());
                         System.out.println (loan.getPayments().get(i).getdatePaid());
                         System.out.println (loan.getPayments().get(i).getloandID());
                         System.out.println (loan.getPayments().get(i).getprinciplePaid());
                    //System.out.println (n);
     }//end try
     catch (IndexOutOfBoundsException indexObException)
     {indexObException.printStackTrace();
     }//end catch
     catch (SQLException sqlException)
     {sqlException.printStackTrace();
     System.out.println("Cannot get connection");
     System.exit(1);
     }//end catch
     catch (ClassNotFoundException classNotFound)
          classNotFound.printStackTrace();
          System.out.println("Class not found");
          System.exit(1);
     finally
          try {
               statement.close();
               connection.close();
          }//end try
     catch (Exception exception)
     exception.printStackTrace();
     System.exit(1);
     }//end catch
     }//end finally
     }//end main
}//end Hw6Dbase

Answer 1

when I query the database using my other program (just doing this to show you whats in the payment table) "select * from payments" I get this.
Admin_ID     Loan_ID     Payment_Date     Payment_Amount     Payment_To_Principle     
0001      0001     2000-05-10 00:00:00     1000.0000     600.0000     
0001     0001     2000-06-10 00:00:00     1000.0000     610.0000     
0001     0002     2000-06-15 00:00:00     1500.0000     1000.0000     
0100     0001     2000-07-10 00:00:00     1000.0000      620.0000     
in this program we only want the payments for loan id '0001'. So in my code you can see that I query as follows:
ResultSet resultSet2 = statement.executeQuery("select * from payments where loan_ID='0001'");
Heres what I get in console when I test "n". (System.out.println(n);)
Payments Received
0
1
1
2
2
2
This is what prints out when I run the program...
Loan Information
Loan id:0001
Start Date:2000-05-05 00:00:00
Amount:10000.00
Annual Rate: 0.06
Loan Duration:5
Payments Received
Loan ID: 0001 //(n=0)
Loan Amount: 1000.0
Date Paid: 2000-05-10 00:00:00
Payment to Principle: 600.0
Balance:9400.0
Loan ID: 0001 //DUPLICATE
Loan Amount: 1000.0
Date Paid: 2000-05-10 00:00:00
Payment to Principle: 600.0
Balance:9400.0
Loan ID: 0001 //DUPLICATE
Loan Amount: 1000.0
Date Paid: 2000-06-10 00:00:00
Payment to Principle: 610.0
Balance:9390.0
Loan ID: 0001
Loan Amount: 1000.0
Date Paid: 2000-05-10 00:00:00
Payment to Principle: 600.0
Balance:9400.0
Loan ID: 0001
Loan Amount: 1000.0
Date Paid: 2000-06-10 00:00:00
Payment to Principle: 610.0
Balance:9390.0
Loan ID: 0001
Loan Amount: 1000.0
Date Paid: 2000-07-10 00:00:00
Payment to Principle: 620.0
Balance:9380.0
Strange order huh? I can't figure it out any ideas?.... here's my code again.
import java.sql.*;
import java.util.ArrayList;
public class Hw6Dbase {
     //Driver NAme and Database URL
     static final String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
     static final String dbaseURL = "jdbc:odbc:homework5";
     public static void main (String args[])
          Loan loan = new Loan();
          Connection connection = null; //connection
          Statement statement = null; //queries
     try
     { Class.forName(driver);
     connection = DriverManager.getConnection(dbaseURL, " ", " ");
     statement = connection.createStatement();
     //query
     {ResultSet resultSet = statement.executeQuery("select * from loan where loanID= '0001'");
     System.out.println("Loan Information");
          while (resultSet.next())
               loan.setloanID(resultSet.getString(1));
               loan.setstartDate(resultSet.getString(2));
               loan.setnoYears(resultSet.getInt(3));
               loan.setannualRate(Double.parseDouble(resultSet.getString(4)));
               loan.setloanAmt(Double.parseDouble(resultSet.getString(5)));
               String loanid = loan.getloanID();
               System.out.println ("Loan id:" + loanid);
          String loanDate = loan.getstartDate();
          double loanAmt = loan.getloanAmt();
          double rate = loan.getannualRate();
          int years = loan.getnoYears();
          System.out.println("Start Date:" + loanDate);
          System.out.printf("Amount:%.2f\n", loanAmt);
          System.out.println("Annual Rate: "+ rate);
          System.out.println("Loan Duration:" + years);
          }//end while
          System.out.println("\nPayments Received");
     ResultSet resultSet2 = statement.executeQuery("select * from payments where loan_ID='0001'");
          while (resultSet2.next())
               Payment payment = new Payment();
                    //set payment attributes
                    payment.setloanID(resultSet2.getString(2));
                    payment.setAmount(Double.parseDouble(resultSet2.getString(4)));
                    payment.setdatePaid(resultSet2.getString(3));
                    payment.setprinciplePaid(Double.parseDouble(resultSet2.getString(5)));
                    int n = loan.getPayments().size();
                    loan.getPayments().add(payment);
                    for (int i= 0; i<= n; i++)
                         double balance = loan.getloanAmt()-loan.getPayments().get(i).getprinciplePaid();
                         //output
                         //System.out.println(n);//test count
                         System.out.println ("Loan ID: " +loan.getPayments().get(i).getloandID());
                         System.out.println ("Loan Amount: " +loan.getPayments().get(i).getAmount());
                         System.out.println ("Date Paid: " +loan.getPayments().get(i).getdatePaid());
                         System.out.println ("Payment to Principle: "+loan.getPayments().get(i).getprinciplePaid());
                         System.out.println ("Balance:" +balance);
                         System.out.println ("\n");
                    }//end for
          }//end of while
     }//end try
     //catch (IndexOutOfBoundsException indexObException)
     //{indexObException.printStackTrace();
     }//end catch
     catch (SQLException sqlException)
     {sqlException.printStackTrace();
     System.out.println("Cannot get connection");
     System.exit(1);
     }//end catch
     catch (ClassNotFoundException classNotFound)
          classNotFound.printStackTrace();
          System.out.println("Class not found");
          System.exit(1);
     finally
          try {
               statement.close();
               connection.close();
          }//end try
     catch (Exception exception)
     exception.printStackTrace();
     System.exit(1);
     }//end catch
     }//end finally
     }//end main
}//end Hw6Dbase