What is an exception?

An exception is an event that disrupts the normal flow of a program. It occurs due to an error or an unforeseen situation.

Exceptions are:

• Checked: require handling or declaration in the method signature (for example, when working with files or networks).
• Unchecked or RuntimeException: usually indicate logical errors in the program and do not require explicit handling (such as division by zero or array bounds violations).
• Errors: represent serious problems from which the program generally should not recover (for example, out of memory).

The exception handling mechanism allows separating error-handling code from the main logical flow of the program. This improves code readability and maintainability.

Exception handling uses try-catch-finally blocks (in Java, C#) or similar constructs (try-except-finally in Python).

try {
    // Code that may cause an exception
    int result = 10 / 0; // ArithmeticException
} catch (ArithmeticException e) {
    // Handling specific exception
    System.err.println("Error: " + e.getMessage());
} catch (Exception e) {
    // Handling any other exceptions
    System.err.println("An unexpected error occurred");
} finally {
    // Code that executes regardless of whether an exception occurred
    System.out.println("Finally block executed");
}