code: @Nullable
    public static Double parseDoubleObj (@Nullable final String sStr, @Nullable final Double aDefault)
    {
      final double dValue = parseDouble (sStr, Double.NaN);
      return Double.isNaN (dValue) ? aDefault : Double.valueOf (dValue);
    }
docs: Parse the given {@link String} as {@link Double}. Note: both the locale
  independent form of a double can be parsed here (e.g. 4.523) as well as a
  localized form using the comma as the decimal separator (e.g. the German
  4,523).
  
  @param sStr
  The string to parse. May be <code>null</code>.
  @param aDefault
  The default value to be returned if the parsed string cannot be
  converted to a double. May be <code>null</code>.
  @return <code>aDefault</code> if the object does not represent a valid
  value.