import java.util.Scanner;
import java.util.InputMismatchException;

public class InputMismatchExceptionDemo
{
    public static void main(String[] args)
    {
        Scanner keyboard = new Scanner(System.in);
        int number = 0; //to keep compiler happy
        boolean done = false;

        while (! done)
        {
            try
            {
                System.out.println("Enter a whole number:");
                number = keyboard.nextInt();
                done = true;
             }
             catch(InputMismatchException e)
             {
                 keyboard.nextLine();
                 System.out.println("Not a correctly written whole number.");
                 System.out.println("Try again.");
             }
        }

        System.out.println("You entered " + number);
    }
}