3.1: write a program to define user defined exceptions and raise them as per the requirement in java ?

 // Define a custom exception class

class CustomException extends Exception {

    public CustomException(String message) {

        super(message);

    }

}

// Create a class that uses the custom exception

class ExceptionDemo {

    public void performTask(int value) throws CustomException {

        if (value < 0) {

            throw new CustomException("Value cannot be negative");

        } else if (value > 100) {

            throw new CustomException("Value cannot exceed 100");

        } else {

            System.out.println("Task performed successfully");

        }

    }

}

public class Main {

    public static void main(String[] args) {

        ExceptionDemo demo = new ExceptionDemo();

        try {

            demo.performTask(50); // No exception will be raised

            demo.performTask(-10); // CustomException will be raised

            demo.performTask(120); // CustomException will be raised

        } catch (CustomException e) {

            System.out.println("Custom Exception Caught: " + e.getMessage());

        }

    }

}