Override a method from an unchecked Exception class in Java

Question

I am trying to override the getMessage() method in the NumberFormatException class in Java, which is an unchecked Exception. For some reason, I am unable to override it. I know it must be something really simple, but can't understand what I could be missing. Could someone please help? Here is my code:

public class NumberFormatSample extends Throwable{

private static void getNumbers(Scanner sc) {
    System.out.println("Enter any two integers between 0-9 : ");
    int a = sc.nextInt();
    int b = sc.nextInt();
    if(a < 0 || a > 9 || b < 0 || b > 9)
        throw new NumberFormatException();
}

@Override
public String getMessage() {
    return "One of the input numbers was not within the specified range!";

}
public static void main(String[] args) {
    try {
        getNumbers(new Scanner(System.in));
    }
    catch(NumberFormatException ex) {
        ex.getMessage();
    }
}

}

Answer 1

EDIT (after your comment).

Seems you are looking for:

public class NumberFormatSample {

    private static void getNumbers(Scanner sc) {
        System.out.println("Enter any two integers between 0-9 : ");
        int a = sc.nextInt();
        int b = sc.nextInt();
        if(a < 0 || a > 9 || b < 0 || b > 9)
            throw new NumberFormatException("One of the input numbers was not within the specified range!");
    }

    public static void main(String[] args) {
        try {
            getNumbers(new Scanner(System.in));
        }
        catch(NumberFormatException ex) {
            System.err.println(ex.getMessage());
        }
    }
}