Question:

Explain what is meant by "exception handling" in computer programming. Give an example code snippet in Java that demonstrates the use of exception handling and provide a step-by-step explanation of how the program runs and handles the exception.

Answer:

Exception handling is a mechanism in computer programming to manage and handle errors that may occur during program execution. It allows programmers to anticipate and gracefully deal with exceptional situations that might otherwise cause the program to terminate abruptly.

Here's an example code snippet in Java that demonstrates the use of exception handling:

import java.util.Scanner;

public class DivisionExample {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter the numerator: ");
        int numerator = scanner.nextInt();

        System.out.print("Enter the denominator: ");
        int denominator = scanner.nextInt();

        try {
            int result = divideNumbers(numerator, denominator);
            System.out.println("Result: " + result);
        } catch (ArithmeticException e) {
            System.out.println("Cannot divide by zero.");
        }

        System.out.println("Program completed.");
    }

    public static int divideNumbers(int numerator, int denominator) {
        return numerator / denominator;
    }
}

Explanation:

1. The program starts by importing the Scanner class and defining a class called DivisionExample.

2. In the main method, a Scanner object is created to read user input from the console.

3. The program asks the user to enter the numerator and denominator values.

4. The try block is used to encapsulate the code that might throw an exception. In this case, the divideNumbers method is called and the numerator and denominator values are passed as arguments. The result of the division is stored in the result variable.

5. If an exception occurs (e.g., if the denominator is zero), the program jumps to the catch block. In this example, an ArithmeticException is caught, indicating that division by zero has occurred. The catch block prints the message "Cannot divide by zero."

6. Whether an exception occurs or not, the program continues to execute the code after the try-catch block, which in this case, is a simple print statement saying "Program completed."

7. Finally, the program ends.

If the user enters a non-zero denominator, the program executes as follows:

• The user is prompted to enter the numerator and denominator values.
• The try block executes the divideNumbers method, dividing the numerator by the denominator.
• The result is printed to the console.
• The program then prints "Program completed."

However, if the user enters zero as the denominator, an ArithmeticException is thrown and caught by the catch block. The program prints "Cannot divide by zero" and then proceeds to print "Program completed."

This example demonstrates how exception handling allows programmers to handle exceptional situations gracefully, preventing the program from crashing or producing incorrect results.