Creating a Java Account Class with Encapsulation and Transaction Methods

Java Encapsulatiion: Exercise-12 with Solution

Write a Java program to create a class called Account with private instance variables accountNumber, accountHolder, and balance. Provide public getter and setter methods to access and modify these variables. Add a method called deposit() that takes an amount and increases the balance by that amount, and a method called withdraw() that takes an amount and decreases the balance by that amount.

Sample Solution:

Java Code:

Account.java

// Define the Account class
public class Account {
    // Private instance variables
    private String accountNumber;
    private String accountHolder;
    private double balance;

    // Public getter for the accountNumber variable
    public String getAccountNumber() {
        return accountNumber;
    }

    // Public setter for the accountNumber variable
    public void setAccountNumber(String accountNumber) {
        this.accountNumber = accountNumber;
    }

    // Public getter for the accountHolder variable
    public String getAccountHolder() {
        return accountHolder;
    }

    // Public setter for the accountHolder variable
    public void setAccountHolder(String accountHolder) {
        this.accountHolder = accountHolder;
    }

    // Public getter for the balance variable
    public double getBalance() {
        return balance;
    }

    // Public setter for the balance variable
    public void setBalance(double balance) {
        this.balance = balance;
    }

    // Method to deposit an amount and increase the balance
    public void deposit(double amount) {
        if (amount > 0) {
            this.balance += amount;
        }
    }

    // Method to withdraw an amount and decrease the balance
    public void withdraw(double amount) {
        if (amount > 0 && this.balance >= amount) {
            this.balance -= amount;
        }
    }  
}

Main.java

public class Main {
    // Main method to test the Account class
    public static void main(String[] args) {
        // Create a new Account object
        Account account = new Account();

        // Set the account number, account holder, and initial balance
        account.setAccountNumber("123456789");
        account.setAccountHolder("Rodolfo Desiree");
        account.setBalance(1000.0);

        // Deposit an amount to the account
        account.deposit(500.0);

        // Withdraw an amount from the account
        account.withdraw(200.0);

        // Print the details of the account
        System.out.println("Account Number: " + account.getAccountNumber());
        System.out.println("Account Holder: " + account.getAccountHolder());
        System.out.println("Balance: $" + account.getBalance());
    }
 }

Output:

Account Number: 123456789
Account Holder: Rodolfo Desiree
Balance: $1300.0

Explanation:

• Private Instance Variables: The accountNumber, accountHolder, and balance variables are declared as private to ensure encapsulation.
• Public Getters and Setters: These methods provide controlled access to the private variables.
• getAccountNumber(): Returns the account number.
• setAccountNumber(String accountNumber): Sets the account number.
• getAccountHolder(): Returns the account holder.
• setAccountHolder(String accountHolder): Sets the account holder.
• getBalance(): Returns the balance.
• setBalance(double balance): Sets the balance.
• deposit Method: Takes an amount and increases the balance by that amount if it's positive.
• withdraw Method: Takes an amount and decreases the balance by that amount if it's positive and less than or equal to the current balance.
• Main Method: Tests the functionality of the Account class by creating an instance, setting its properties, performing transactions, and printing the details.

Note on Encapsulation

Encapsulation works in the above exercise by:

• Hiding Data: The private instance variables accountNumber, accountHolder, and balance are not accessible directly from outside the class.
• Controlled Access: The public getter and setter methods provide controlled access to the private variables, allowing for validation and modification when necessary.
• Data Integrity: Encapsulation helps maintain data integrity by ensuring that the internal state of the object can only be changed through well-defined methods.

Java Code Editor:

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