code: public static Date parseTimestamp(@Nullable String string) {
          Date date = null;
          try {
              if (string != null) {
                  date = ISO8601Utils.parse(string, new ParsePosition(0));
              }
          } catch (ParseException e) {
              throw Throwables.propagate(e);
          }
          return date;
      }
docs: Parses an ISO 8601 date+time string into a Java Date object.