Exception Handling

Exception Handling in Java is a powerful mechanism that handles runtime errors to maintain the normal flow of application execution. Java provides a robust and object-oriented way to handle exceptions using try, catch, throw, throws, and finally blocks.

Why Use Exception Handling?

  • Avoid abnormal termination of the program.
  • Gracefully handle unexpected situations like file not found, divide by zero, etc.
  • Help in debugging and maintaining the code.

Keywords in Exception Handling

  1. try – Defines a block of code to test for errors.
  2. catch – Defines a block of code to handle errors.
  3. finally – Defines a block of code that will always execute after try/catch, regardless of the outcome.
  4. throw – Used to explicitly throw an exception.
  5. throws – Declares exceptions that a method might throw.

Example:

public class ExceptionExample {
    public static void main(String[] args) {
        try {
            int result = 10 / 0;  // ArithmeticException
        } catch (ArithmeticException e) {
            System.out.println("Error: " + e.getMessage());
        } finally {
            System.out.println("This will always execute.");
        }
    }
}

Output:

Error: / by zero
This will always execute.

Types of Exceptions

  1. Checked Exceptions – Must be handled at compile time (e.g., IOException).
  2. Unchecked Exceptions – Occur during runtime and are not required to be caught (e.g., ArithmeticException, NullPointerException).
  3. Errors – Serious problems not intended to be caught (e.g., OutOfMemoryError).

🔗 Related Notes