code: public static void validateReservedDatastreams(DOReader reader)
              throws ValidationException {
          try {
              for (Datastream ds: reader.GetDatastreams(null, null)) {
                  if ("X".equals(ds.DSControlGrp) || "M".equals(ds.DSControlGrp)) {
                      validateReservedDatastream(PID.getInstance(reader.GetObjectPID()),
                                                 ds.DatastreamID,
                                                 ds);
                  }
              }
          } catch (ValidationException e) {
              throw e;
          } catch (ServerException e) {
              throw new FaultException(e);
          }
      }
docs: Validates the latest version of all reserved datastreams in the given
  object.