How to check an IBAN number using the Apache IBANCheckDigit?

kramer65 picture kramer65 · Dec 4, 2013 · Viewed 9.7k times · Source

In my Android app, I'm trying to check if an IBAN bank account number is valid. This supposedly can be done using the Apache IBANCheckDigit. I now try do so as follows:

IBANCheckDigit a = new IBANCheckDigit();
try {
    String checkDigit = a.calculate("MY_IBAN_NUMBER_HERE");
    Boolean b = a.isValid(checkDigit);
    Log.e("isValid: ", b.toString());
} catch (CheckDigitException e) {
    Log.e(this, "THIS IS AN ERROR");
}

This however, always prints false. Even if I insert my own (correct) IBAN-number, it also gives a false.

Does anybody know how to use this Apache IBANCheckDigit? Any tips are welcome!

Answer

Joni picture Joni · Dec 4, 2013

To check if the IBAN check digits are valid you should use the isValid method only:

Boolean b = a.isValid("MY_IBAN_NUMBER_HERE");
Log.e("isValid: ", b.toString());

The calculate method would compute the check digits if you did not know them already.