Use the following files:

AccountTester.java

/**
   This program tests the BankAccount class and its subclasses.
*/
public class AccountTester
{
   public static void main(String[] args)
   {
      SavingsAccount momsSavings = new SavingsAccount(5);
      CheckingAccount harrysChecking = new CheckingAccount(0);
      
      test(momsSavings);
      System.out.println(momsSavings.getBalance());      
      System.out.println("Expected: 6300");
      
      test(harrysChecking);
      System.out.println(harrysChecking.getBalance());      
      System.out.println("Expected: 5996");
   }

   public static void test(BankAccount account)
   {
      for (int i = 1; i <= 5; i++)
      {
         if (i % 2 == 1)
            account.deposit(i * 1000);
         else
            account.withdraw(i * 500);
      }

      account.endOfMonth();
   }
}

BankAccount.java

/**
   A bank account has a balance that can be changed by 
   deposits and withdrawals.
*/
public abstract class BankAccount
{  
   private double balance; 

   /**
      Constructs a bank account with a zero balance.
   */
   public BankAccount()
   {  
      balance = 0;
   }

   /**
      Constructs a bank account with a given balance.
      @param initialBalance the initial balance
   */
   public BankAccount(double initialBalance)
   {  
      balance = initialBalance;
   }
 
   /**
      Deposits money into the bank account.
      @param amount the amount to deposit
   */
   public void deposit(double amount) 
   {  
      balance = balance + amount;
   }

   /**
      Withdraws money from the bank account.
      @param amount the amount to withdraw
   */
   public void withdraw(double amount) 
   {  
      balance = balance - amount;
   }

   /**
      Gets the current balance of the bank account.
      @return the current balance
   */
   public double getBalance()
   {  
      return balance; 
   }
   

   /**
      Abstract method that performs the end of month adjustment.
   */
   public abstract void endOfMonth();
}