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PONullPointException in Simple Program, Cannot Find Fix
 

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  1. PONullPointException in Simple Program, Cannot Find Fix
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    <p>This is the exception I am getting:</p> <pre><code>Exception in thread "main" java.lang.NullPointerException at BankAccountDemo.DisplayAccountFees(BankAccountDemo.java:91) at BankAccountDemo.main(BankAccountDemo.java:30) </code></pre> <p>I am also getting this exception whenever I try to print or view all the accounts with the fees assessed. </p> <p>Here is my driver program. It has 5 classes, which are also below. One of them is an abstract class with 3 descendants. </p> <p>DRIVER</p> <pre><code>import java.io.*; import java.util.Scanner; import java.util.ArrayList; public class BankAccountDemo { public static void main(String[] args) { while(true) { Scanner keyboard = new Scanner(System.in); System.out.println("=========Menu========"); System.out.println("1. Add an account."); System.out.println("2. To print the names of all accounts together with the fees assessed"); System.out.println("3. To print all accounts together with owner information"); System.out.println("4. To exit program"); System.out.println("Your choice: "); int input = keyboard.nextInt(); switch(input) { case 1: InputAccount(); break; case 2: DisplayAccountFees(); break; case 3: ShowAccount(); break; default: PrintToFile(); System.exit(0); } } } private static void InputAccount() { System.out.println("Please enter user data as prompted..."); System.out.println("Please enter account type: Press '1' for Checking, '2' for Savings, '3' for Loan"); System.out.println("Account Type: "); Scanner keyboard = new Scanner(System.in); int type = keyboard.nextInt(); switch(type) { case 1: { Checking aChecking = new Checking(); aChecking.AddAccount(); checkAccounts.add(aChecking); break; } case 2: { Savings aSavings = new Savings(); aSavings.AddAccount(); savingsAccounts.add(aSavings); break; } case 3: { Loan aLoan = new Loan(); aLoan.AddAccount(); loanAccounts.add(aLoan); break; } } } private static void DisplayAccountFees() { for (int n=0; n &lt; savingsAccounts.size(); n++) { Savings aSavings = savingsAccounts.get(n); Person aPerson = aSavings.getAccountHolder(); System.out.println("Total Fees for: " +aPerson.getPersonName()); System.out.println("with the account number: " +aSavings.getAcctNumber()); System.out.println("are: " + aSavings.accountFee()); } for (int n=0; n &lt; checkAccounts.size(); n++) { Checking aChecking = checkAccounts.get(n); Person aPerson = aChecking.getAccountHolder(); System.out.println("Total Fees for: " +aPerson.getPersonName()); System.out.println("with the account number: " +aChecking.getAcctNumber()); System.out.println("are: " + aChecking.accountFee()); } for(int n=0; n &lt; loanAccounts.size(); n++) { Loan aLoan = loanAccounts.get(n); Person aPerson = aLoan.getAccountHolder(); System.out.println("Total Fees for: " +aPerson.getPersonName()); System.out.println("with the account number: " +aLoan.getAcctNumber()); System.out.println("are: " + aLoan.accountFee()); } } private static void ShowAccount() { for(int n=0; n &lt; savingsAccounts.size(); n++) { Savings aSavings = savingsAccounts.get(n); aSavings.DisplayData(); } for(int n=0; n &lt; checkAccounts.size(); n++) { Checking aChecking = checkAccounts.get(n); aChecking.DisplayData(); } for(int n=0; n &lt; loanAccounts.size(); n++) { Loan aLoan = loanAccounts.get(n); aLoan.DisplayData(); } } private static void PrintToFile() { try { FileOutputStream fileOutput = new FileOutputStream("Accounts.dat"); ObjectOutputStream printFile = new ObjectOutputStream(fileOutput); for (int n=0; n &lt; loanAccounts.size(); n++) { Loan aLoan = loanAccounts.get(n); aLoan.PrintAccountToFile(printFile); } for (int n=0; n &lt; checkAccounts.size(); n++) { Checking aChecking = checkAccounts.get(n); aChecking.PrintAccountToFile(printFile); } for (int n=0; n &lt; savingsAccounts.size(); n++) { Savings aSavings = savingsAccounts.get(n); aSavings.PrintAccountToFile(printFile); } printFile.close(); fileOutput.close(); } catch(IOException ex) { } } private static ArrayList&lt;Checking&gt; checkAccounts = new ArrayList&lt;Checking&gt;(); private static ArrayList&lt;Savings&gt; savingsAccounts = new ArrayList&lt;Savings&gt;(); private static ArrayList&lt;Loan&gt; loanAccounts = new ArrayList&lt;Loan&gt;(); } </code></pre> <p>ACCOUNT CLASS</p> <pre><code>import java.io.IOException; import java.io.ObjectOutputStream; import java.util.Scanner; public abstract class Account { private String bankName; private String bankAddress; private String acctNumber; private String acctType; private double balance; private Person accountHolder; public Account() { } public Person setAccountHolder(Person holder) { return holder; } public void setBankName(String newBankName) { bankName = newBankName; } public void setAddress(String newBankAddress) { bankAddress = newBankAddress; } public void setAcctNumber(String newAcctNumber) { acctNumber = newAcctNumber; } public void setBalance(double newBalance) { balance = newBalance; } public void setAcctType(String newAcctType) { acctType = newAcctType; } public Person getAccountHolder() { return accountHolder; } public String getBankName() { return bankName; } public String getAddress() { return bankAddress; } public String getAcctNumber() { return acctNumber; } public String getAcctType() { return acctType; } public double getBalance() { return balance; } public abstract double accountFee(); public abstract void DisplayData(); public abstract void AddAccount(); public abstract void PrintAccountToFile(ObjectOutputStream printFile); public void readInputAccount() { Scanner keyboard = new Scanner(System.in); System.out.println("Enter the name of your bank: "); bankName = keyboard.nextLine(); System.out.println("Enter the address of your bank: "); bankAddress = keyboard.nextLine(); System.out.println("Enter your account number: "); acctNumber = keyboard.nextLine(); System.out.println("Enter your current balance: "); balance = keyboard.nextDouble(); } public void PrintBankInfo(ObjectOutputStream printFile) { try { printFile.writeUTF("------------------------------------------"); printFile.writeUTF(" Bank information: "); printFile.writeUTF("------------------------------------------"); printFile.writeUTF("Bank name: " + getBankName()); printFile.writeUTF("Bank Address: " + getAddress()); } catch(IOException ex) { } } public void DisplayBankInfo() { System.out.println("------------------------------------------"); System.out.println(" Bank information: "); System.out.println("------------------------------------------"); System.out.println("Bank name: " + getBankName()); System.out.println("Bank Address: " + getAddress()); } } </code></pre> <p>CHECKING CLASS</p> <pre><code>import java.util.Scanner; import java.io.*; public class Checking extends Account { private double monthFee; private int checksAllowed; private int checksUsed; public Checking() { } public double accountFee() { int tooManyChecks = checksUsed - checksAllowed; double fee = monthFee + (3.00 * tooManyChecks); return fee; } public double getMonthFee() { return monthFee; } public int getChecksAllowed() { return checksAllowed; } public int getChecksUsed() { return checksUsed; } public void setMonthFee(double newMonthFee) { monthFee = newMonthFee; } public void setChecksAllowed(int newChecksAllowed) { checksAllowed = newChecksAllowed; } public void setChecksUsed(int newChecksUsed) { checksUsed = newChecksUsed; } public void AddAccount() { Person aPerson = new Person(); aPerson.personInput(); setAccountHolder(aPerson); readInputAccount(); Scanner keyboard = new Scanner(System.in); System.out.println("Please enter the monthly fee: "); monthFee = keyboard.nextDouble(); System.out.println("Please enter the number of free checks allowed: "); checksAllowed = keyboard.nextInt(); System.out.println("Please enter the number of checks used: "); checksUsed = keyboard.nextInt(); } public void DisplayData() { Person aPerson = getAccountHolder(); aPerson.DisplayPersonInfo(); DisplayBankInfo(); System.out.println("------------------------------------------"); System.out.println(" Account information: "); System.out.println("Account Type : Checking"); System.out.println("Bank account number :" + getAcctNumber()); System.out.println("Account balance :" + getBalance()); System.out.println("Monthly fee :" + getMonthFee()); System.out.println("Number of checks used :" + getChecksUsed()); System.out.println("Number of free checks :" + getChecksAllowed()); } public void PrintAccountToFile(ObjectOutputStream printFile) { try { Person aPerson = getAccountHolder(); aPerson.PrintInfo(printFile); PrintBankInfo(printFile); printFile.writeUTF("------------------------------------------"); printFile.writeUTF(" Account information: "); printFile.writeUTF("Account Type : Checking"); printFile.writeUTF("Bank account number :" + getAcctNumber()); printFile.writeUTF("Account balance :" + getBalance()); printFile.writeUTF("Monthly fee :" + getMonthFee()); printFile.writeUTF("Number of checks used :" + getChecksUsed()); printFile.writeUTF("Number of free checks :" + getChecksAllowed()); printFile.writeUTF("Fees accessed : " + accountFee()); } catch(IOException ex) { } } } </code></pre> <p>LOAN CLASS</p> <pre><code>import java.util.Scanner; import java.io.*; public class Loan extends Account { private double monthPayment; private int daysOverDue; public Loan() { } public void setMonthPayment(double newMonthPayment) { monthPayment = newMonthPayment; } public void setDaysOverDue(int newDaysOverDue) { daysOverDue = newDaysOverDue; } public double getMonthPayment() { return monthPayment; } public int getDaysOverDue() { return daysOverDue; } public double accountFee() { double fee = 0.001 * monthPayment * daysOverDue; return fee; } public void AddAccount(){ Scanner keyboard = new Scanner(System.in); Person aPerson = new Person(); aPerson.personInput(); setAccountHolder(aPerson); readInputAccount(); System.out.println("Please enter the monthly payment amount: "); monthPayment = keyboard.nextDouble(); System.out.println("Please enter the number of days past the grace period: "); daysOverDue = keyboard.nextInt(); } public void DisplayData() { Person aPerson = getAccountHolder(); aPerson.DisplayPersonInfo(); } public void PrintAccountToFile(ObjectOutputStream printFile) { try { Person aPerson = getAccountHolder(); aPerson.PrintInfo(printFile); printFile.writeUTF("------------------------------------------"); printFile.writeUTF(" Account information: "); printFile.writeUTF("Account Type: Loan"); printFile.writeUTF("Bank account number: " + getAcctNumber()); printFile.writeUTF("Account balance: " + getBalance()); printFile.writeUTF("Monthly payment amount: " + getMonthPayment()); printFile.writeUTF("Number of days past the grace period: " + getDaysOverDue()); printFile.writeUTF("Fees assessed: " + accountFee()); } catch(IOException ex) { } } } </code></pre> <p>SAVINGS CLASS</p> <pre><code>import java.io.*; import java.util.Scanner; public class Savings extends Account { private double minBal; private double intRate; private double avgBal; public Savings() { } public double accountFee() { double fee = 0.00; if (avgBal &lt; minBal) { fee = 50.00; } return fee; } public double getMinBal() { return minBal; } public double getIntRate() { return minBal; } public double getAvgBal() { return avgBal; } public void setMinBal(double newMinBal) { minBal = newMinBal; } public void setIntRate(double newIntRate) { minBal = newIntRate; } public double getChecks() { return intRate; } public void setChecks(double newIntRate) { intRate = newIntRate; } public void setAvgBal(double newAvgBal) { avgBal = newAvgBal; } public void AddAccount() { Scanner keyboard = new Scanner(System.in); Person aPerson = new Person(); aPerson.personInput(); setAccountHolder(aPerson); readInputAccount(); System.out.println("Please enter the minimum balance: "); minBal = keyboard.nextDouble(); System.out.println("Please enter the average balance: "); avgBal = keyboard.nextDouble(); System.out.println("Please enter interest rate"); intRate = keyboard.nextDouble(); } public void DisplayData() { Person aPerson = getAccountHolder(); aPerson.DisplayPersonInfo(); DisplayBankInfo(); System.out.println("------------------------------------------"); System.out.println(" Account information: "); System.out.println("Account Type: Savings Account"); System.out.println("Bank account number: " + getAcctNumber()); System.out.println("Account balance: " + getBalance()); System.out.println("Minimum balance: " + getMinBal()); System.out.println("Average balance: " + getAvgBal()); System.out.println("Interest rate: " + getIntRate()); } public void PrintAccountToFile(ObjectOutputStream printFile) { try { Person aPerson = getAccountHolder(); aPerson.PrintInfo(printFile); PrintBankInfo(printFile); printFile.writeUTF("------------------------------------------"); printFile.writeUTF(" Account information: "); printFile.writeUTF("Account Type: Savings Account"); printFile.writeUTF("Bank account number: " + getAcctNumber()); printFile.writeUTF("Account balance: " + getBalance()); printFile.writeUTF("Minimum balance: " + getMinBal()); printFile.writeUTF("Average balance: " + getAvgBal()); printFile.writeUTF("Interest rate: " + getIntRate()); printFile.writeUTF("Fees assessed: " + accountFee()); } catch(IOException ex) { } } } </code></pre>
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