FactorialExceptionDemo.java

class FactorialProcessor {
    
    // Method that accepts the integer and propagates the exception if it's negative
    public void acceptInteger(int number) throws IllegalArgumentException {
        if (number < 0) {
            // Throwing the exception to be handled by the caller
            throw new IllegalArgumentException("Factorial is not defined for negative numbers. Value provided: " + number);
        } else {
            // If positive or zero, call the calculation method
            calculateAndDisplayFactorial(number);
        }
    }

    // Method to calculate and display the factorial
    private void calculateAndDisplayFactorial(int number) {
        long factorial = 1;
        for (int i = 1; i <= number; i++) {
            factorial *= i;
        }
        System.out.println("The factorial of " + number + " is: " + factorial);
    }
}

// 2. Main Driver Class (PascalCase)
public class FactorialExceptionDemo {
    public static void main(String[] args) {
        System.out.println("--- Factorial Exception Handling Demo ---");
        
        FactorialProcessor processor = new FactorialProcessor();

        // Testing the try-catch block for handling the propagated exception
        try {
            // This will succeed
            System.out.println("Attempting to calculate factorial of 5:");
            processor.acceptInteger(5);
            
            // This will trigger the IllegalArgumentException
            System.out.println("\nAttempting to calculate factorial of -3:");
            processor.acceptInteger(-3);
            
        } catch (IllegalArgumentException e) {
            // Catching the exception propagated from the FactorialProcessor class
            System.out.println("Exception Caught in Main Class -> " + e.getMessage());
        }
    }
}