Comments Interview Questions and Answers

public class DiscountCalculator {
    public static void main(String[] args) {
        double price = 1000.0;
        // Premium customers receive a 10% discount.
        double finalPrice = price - price * 0.10;
        System.out.println(finalPrice);
    }
}

/**
 * Demonstrates the main Java comment types.
 */
public class CommentTypes {
    public static void main(String[] args) {
        // Stores the application name.
        String applicationName = "Java Portal";
        /*
         * Displays the application name
         * on the console.
         */
        System.out.println(applicationName);
    }
}

/**
 * Calculates the sum of two numbers.
 *
 * @param first first number
 * @param second second number
 * @return sum of both numbers
 */
public class Calculator {
    public static int add(int first, int second) {
        // Return the calculated sum.
        return first + second;
    }
    public static void main(String[] args) {
        /*
         * Calls the add method and
         * displays the returned result.
         */
        System.out.println(add(10, 20));
    }
}

public class LoginPolicy {
    public static void main(String[] args) {
        int failedAttempts = 3;
        // Lock the account after three failed login attempts.
        boolean accountLocked = failedAttempts >= 3;
        System.out.println(accountLocked);
    }
}

public class MultiLineCommentExample {
    public static void main(String[] args) {
        /*
         * The shipping charge is waived
         * when the order total is at least 500.
         */
        double orderTotal = 750.0;
        boolean freeShipping = orderTotal >= 500.0;
        System.out.println(freeShipping);
    }
}

/**
 * Provides basic mathematical operations.
 */
public class Calculator {
    /**
     * Adds two integer values.
     *
     * @param first first value
     * @param second second value
     * @return sum of both values
     */
    public int add(int first, int second) {
        return first + second;
    }
}

/**
 * Represents a customer account.
 */
public class CustomerAccount {
    private final int accountId;
    /**
     * Creates a customer account.
     *
     * @param accountId unique account identifier
     */
    public CustomerAccount(int accountId) {
        this.accountId = accountId;
    }
    /**
     * Returns the account identifier.
     *
     * @return account identifier
     */
    public int getAccountId() {
        return accountId;
    }
}

/**
 * Provides division operations.
 *
 * @author Development Team
 * @since 1.0
 */
public class DivisionService {
    /**
     * Divides one number by another.
     *
     * @param dividend value to divide
     * @param divisor value used as the divisor
     * @return division result
     * @throws IllegalArgumentException if the divisor is zero
     */
    public double divide(double dividend, double divisor) {
        if (divisor == 0) {
            throw new IllegalArgumentException("Divisor cannot be zero");
        }
        return dividend / divisor;
    }
}

/**
 * Manages product information.
 */
public class ProductService {
    /**
     * Default product limit.
     */
    public static final int DEFAULT_LIMIT = 20;
    /**
     * Finds a product by its identifier.
     *
     * @param productId product identifier
     * @return formatted product information
     */
    public String findProduct(int productId) {
        // This regular comment explains internal implementation.
        return "Product-" + productId;
    }
}

public class CommentExecutionExample {
    public static void main(String[] args) {
        // This comment is ignored during compilation.
        int result = 10 + 20;
        // Comment symbols inside a string are normal characters.
        String text = "// This is string content";
        System.out.println(result);
        System.out.println(text);
    }
}

public class InlineCommentExample {
    public static void main(String[] args) {
        int total = 10 /* first value */ + 20;
        printMessage(
            "Java", // First argument
            total
        );
    }
    public static void printMessage(String language, int value) {
        System.out.println(language + ": " + value);
    }
}

public class CommentPerformanceExample {
    public static void main(String[] args) {
        // This explanation does not affect runtime execution.
        int result = calculateTotal(10, 20);
        System.out.println(result);
    }
    public static int calculateTotal(int first, int second) {
        /*
         * This block comment is not included
         * as executable JVM instructions.
         */
        return first + second;
    }
}

public class WithdrawalService {
    private static final double DAILY_LIMIT = 50000.0;
    public boolean canWithdraw(double requestedAmount) {
        // Regulatory policy limits the total daily withdrawal amount.
        return requestedAmount > 0 && requestedAmount <= DAILY_LIMIT;
    }
    public static void main(String[] args) {
        WithdrawalService service = new WithdrawalService();
        System.out.println(service.canWithdraw(20000.0));
    }
}

public class PaymentService {
    public void processPayment(double amount) {
        // TODO: Add currency validation before release.
        // FIXME: Replace this temporary rounding logic.
        double roundedAmount = Math.round(amount * 100.0) / 100.0;
        // NOTE: The payment gateway accepts two decimal places.
        System.out.println(roundedAmount);
    }
    public static void main(String[] args) {
        PaymentService service = new PaymentService();
        service.processPayment(125.678);
    }
}

public class OrderValidator {
    private static final double MINIMUM_ORDER_AMOUNT = 100.0;
    /**
     * Checks whether an order meets the minimum purchase requirement.
     *
     * @param orderAmount total order amount
     * @return true when the order amount is valid
     */
    public boolean isValid(double orderAmount) {
        // The minimum protects against processing costs on very small orders.
        return orderAmount >= MINIMUM_ORDER_AMOUNT;
    }
    public static void main(String[] args) {
        OrderValidator validator = new OrderValidator();
        System.out.println(validator.isValid(150.0));
    }
}