1. What is an Exception?

An exception is an unexpected event that occurs during program execution and disrupts the normal flow of the program.

For example:

int a = 10;
int b = 0;

int result = a / b;

This causes:

ArithmeticException

because division by zero is not allowed.

Other examples include trying to access an invalid array index or trying to use a null reference.

2. Why Exception Handling?

Exception handling allows us to handle errors gracefully instead of allowing the program to terminate unexpectedly.

Without handling:

int result = 10 / 0;

System.out.println("Hello");

The exception occurs and "Hello" won't execute normally.

With handling:

try {
    int result = 10 / 0;
}
catch (ArithmeticException e) {
    System.out.println("Cannot divide by zero");
}

The exception is handled and the program can continue.

Exception handling → detect, handle, and recover from exceptional situations.

3. Exception Hierarchy