code: public static double toDouble(@Nullable final String doubleStr) {
          if (!isValidDouble(doubleStr)) {
              throw new IllegalArgumentException(doubleStr + ExceptionValues.EXCEPTION_DELIMITER + ExceptionValues.INVALID_DOUBLE_VALUE);
          }
          final String stripedDouble = StringUtils.strip(doubleStr);
          return NumberUtils.createDouble(stripedDouble);
      }
docs: Given an double string if it's a valid double (see isValidDouble) it converts it into an double otherwise it throws an exception
  
  @param doubleStr the double to convert
  @return the double value of the doubleStr
  @throws IllegalArgumentException if the passed double string is not a valid double