private List<Integer> extractDigits(final String value) throws NumberFormatException {
    final List<Integer> digits = new ArrayList<>(value.length());
    final char[] chars = value.toCharArray();
    for (final char c : chars) {
      digits.add(this.extractDigit(c));
    }
    return digits;
  }
private List < Integer > extractDigits ( final String value ) throws NumberFormatException { final List < Integer > digits = new ArrayList < > ( value . length ( ) ) ; final char [ ] chars = value . toCharArray ( ) ; for ( final char c : chars ) { digits . add ( this . extractDigit ( c ) ) ; } return digits ; }
Parses the {@link String} value as a {@link List} of {@link Integer} objects.

@param value the input string to be parsed

@return List of {@code Integer} objects.

@throws NumberFormatException in case any of the characters is not a digit