Exception Handling in Java

What is an Exception?

An exception is an event that disrupts the normal execution of a program.

Example:

int a = 10 / 0;

Output:

ArithmeticException

Here, dividing by zero causes an exception.

Exception Handling

Exception handling is a mechanism used to handle runtime errors so the program does not terminate suddenly.

It allows the program to continue execution normally.

Why Exception Handling is Used

Without exception handling:

• Program stops immediately when an error occurs.

With exception handling:

• Error can be handled properly.


• Remaining code can continue executing.

Example:

class Test {

    public static void main(String[] args) {



        System.out.println("Start");



        int a = 10 / 0;



        System.out.println("End");

    }

}

Output

Start

Exception in thread "main" java.lang.ArithmeticException

End will not execute.

try-catch in Java

• try-catch is used to handle exceptions.

Syntax

try {

    // risky code

}

catch(ExceptionType e) {

    // handling code

}

Example of try-catch

class Test {

    public static void main(String[] args) {



        try {

            int a = 10 / 0;

        }



        catch(ArithmeticException e) {

            System.out.println("Cannot divide by zero");

        }



        System.out.println("Program continues");

    }

}

Output:

Cannot divide by zero

Program continues

Real-Time Example

ATM application:

• If wrong PIN is entered,program should show error message instead of stopping.




• Banking apps, websites, and mobile apps use exception handling to avoid crashes.