code: public Iterable<ObjectResult> getFailedObjectResults() {
          List<ObjectResult> result = new ArrayList<>();
          for (ObjectResult objResult : m_objResultList) {
              if (objResult.isFailed()) {
                  result.add(objResult);
              }
          }
          return result;
      }
docs: Get the {@link ObjectResult}s for objects whose failed in this batch. When an
  object update fails, if the original DBObject had no object ID, none will exist in
  the corresponding ObjectResult either.
  
  @return  Set of object IDs whose update failed.