BankAccount and SavingsAccount Classes in Java

Last update on May 17 2025 13:18:33 (UTC/GMT +8 hours)

Write a Java program to create a class called "BankAccount" with attributes for account number, account holder's name, and balance. Include methods for depositing and withdrawing money, as well as checking the balance. Create a subclass called "SavingsAccount" that adds an interest rate attribute and a method to apply interest.

Sample Solution:

Java Code:

BankAccount.java

// Define the BankAccount class
public class BankAccount {

    // Attribute for account number
    private String accountNumber;
    
    // Attribute for account holder's name
    private String accountHolderName;
    
    // Attribute for account balance
    private double balance;

    // Constructor to initialize BankAccount object
    public BankAccount(String accountNumber, String accountHolderName, double initialBalance) {
        this.accountNumber = accountNumber;
        this.accountHolderName = accountHolderName;
        this.balance = initialBalance;
    }

    // Method to deposit money into the account
    public void deposit(double amount) {
        if (amount > 0) {
            balance += amount;
            System.out.println("Deposited: " + amount + ". New balance: " + balance);
        } else {
            System.out.println("Deposit amount must be positive.");
        }
    }

    // Method to withdraw money from the account
    public void withdraw(double amount) {
        if (amount > 0 && amount <= balance) {
            balance -= amount;
            System.out.println("Withdrew: " + amount + ". New balance: " + balance);
        } else {
            System.out.println("Insufficient balance or invalid amount.");
        }
    }

    // Method to check the account balance
    public double checkBalance() {
        return balance;
    }

    // Getter method for account number
    public String getAccountNumber() {
        return accountNumber;
    }

    // Getter method for account holder's name
    public String getAccountHolderName() {
        return accountHolderName;
    }
}

The above Java code defines a BankAccount class with three attributes: accountNumber, accountHolderName, and balance. It includes a constructor to initialize these attributes when an object of this class is created. The class also provides methods to:

Deposit money (deposit): Adds a specified amount to the balance if the amount is positive.
Withdraw money (withdraw): Subtracts a specified amount from the balance if the amount is positive and does not exceed the current balance.
Check balance (checkBalance): Returns the current balance.
Get account number (getAccountNumber): Returns the account number.
Get the account holder's name (getAccountHolderName): Returns the account holder's name.

SavingsAccount.java

// Define the SavingsAccount subclass that extends BankAccount
class SavingsAccount extends BankAccount {

    // Attribute for interest rate
    private double interestRate;

    // Constructor to initialize SavingsAccount object
    public SavingsAccount(String accountNumber, String accountHolderName, double initialBalance, double interestRate) {
        super(accountNumber, accountHolderName, initialBalance); // Call the constructor of the superclass
        this.interestRate = interestRate;
    }

    // Method to apply interest to the balance
    public void applyInterest() {
        double interest = checkBalance() * interestRate / 100; // Calculate interest
        deposit(interest); // Add interest to the balance
        System.out.println("Interest applied: " + interest + ". New balance: " + checkBalance());
    }

    // Getter method for interest rate
    public double getInterestRate() {
        return interestRate;
    }

    // Setter method for interest rate
    public void setInterestRate(double interestRate) {
        if (interestRate > 0) {
            this.interestRate = interestRate;
        } else {
            System.out.println("Interest rate must be positive.");
        }
    }
}

The above Java code defines a SavingsAccount class that extends the BankAccount class, inheriting its attributes and methods. The SavingsAccount class adds a new attribute, interestRate, which represents the interest rate for the savings account. The class includes:

Constructor: Initializes the SavingsAccount object with the account number, account holder's name, initial balance, and interest rate by calling the superclass (BankAccount) constructor for the common attributes.
Method to apply interest (applyInterest): Calculates interest based on the current balance and interest rate, then deposits interest into the account.
Getter method for interest rate (getInterestRate): Returns the current interest rate.
Setter method for interest rate (setInterestRate): Updates the interest rate if the provided rate is positive, ensuring it is a valid interest rate.

Main.java

// Main class to test the BankAccount and SavingsAccount classes
public class Main {
    public static void main(String[] args) {
        // Create a BankAccount object
        BankAccount account = new BankAccount("123456789", "Henri Lionel", 1000.0);
		System.out.println("Current balance: " + account.checkBalance()); // Check balance
        account.deposit(4000.0); // Deposit money
        account.withdraw(3000.0); // Withdraw money
        System.out.println("Current balance: " + account.checkBalance()); // Check balance

        // Create a SavingsAccount object
        SavingsAccount savings = new SavingsAccount("888888888", "Amphitrite Jun", 2000.0, 5.0);
        savings.applyInterest(); // Apply interest
        System.out.println("Savings account balance: " + savings.checkBalance()); // Check balance
    }
}

The above Java code defines a Main class with a main method to test the BankAccount and SavingsAccount classes. The main method demonstrates the creation and usage of these classes:

Create a BankAccount object: An instance of BankAccount is created with the account number "123456789", account holder's name "Henri Lionel", and an initial balance of 1000.0. The current balance is printed.
Deposit money: 4000.0 is deposited into the BankAccount.
Withdraw money: 3000.0 is withdrawn from the BankAccount.
Check balance: The current balance is printed again.
Create a SavingsAccount object: An instance of SavingsAccount is created with the account number "888888888", account holder's name "Amphitrite Jun", an initial balance of 2000.0, and an interest rate of 5.0.
Apply interest: Interest is applied to the SavingsAccount, and the new balance is printed.

This code tests the functionality of depositing, withdrawing, and applying interest in bank accounts.

Sample Output:

Current balance: 1000.0
Deposited: 4000.0. New balance: 5000.0
Withdrew: 3000.0. New balance: 2000.0
Current balance: 2000.0
Deposited: 100.0. New balance: 2100.0
Interest applied: 100.0. New balance: 2100.0
Savings account balance: 2100.0

For more Practice: Solve these Related Problems:

Write a Java program where the "BankAccount" class prevents withdrawals that would result in a negative balance.
Write a Java program to implement a feature in the "SavingsAccount" class that automatically applies interest every month.
Write a Java program where the "BankAccount" class tracks the largest deposit and withdrawal for each account.
Write a Java program to modify the "BankAccount" class so that a joint account can have multiple owners.

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