import java.util.Scanner;
import java.util.InputMismatchException;
//=================================================================================================
public class ReadSafely {
//-------------------------------------------------------------------------------------------------
    private static final Scanner keyboard = new Scanner(System.in);
//-------------------------------------------------------------------------------------------------
    public static void main(String[] args) {

        double doubleValue = 0.0;
        boolean readSuccessful = false;

        while (! readSuccessful) {
            System.out.print("Please enter a real number : ");
            try {
                doubleValue = keyboard.nextDouble();
                readSuccessful = true;
            } catch (InputMismatchException e) {
                System.out.println("That is not a double");
            }
            keyboard.nextLine();
        }
        System.out.println("The value is " + doubleValue);
    }
//-------------------------------------------------------------------------------------------------
}
//=================================================================================================