code: @POST
      @Path("/bulk/classification")
      @Consumes({Servlets.JSON_MEDIA_TYPE, MediaType.APPLICATION_JSON})
      @Produces(Servlets.JSON_MEDIA_TYPE)
      public void addClassification(ClassificationAssociateRequest request) throws AtlasBaseException {
          AtlasPerfTracer perf = null;
  
          try {
              if (AtlasPerfTracer.isPerfTraceEnabled(PERF_LOG)) {
                  perf = AtlasPerfTracer.getPerfTracer(PERF_LOG, "EntityREST.addClassification(" + request  + ")");
              }
  
              AtlasClassification classification = request == null ? null : request.getClassification();
              List<String>        entityGuids    = request == null ? null : request.getEntityGuids();
  
              if (classification == null || StringUtils.isEmpty(classification.getTypeName())) {
                  throw new AtlasBaseException(AtlasErrorCode.INVALID_PARAMETERS, "no classification");
              }
  
              if (CollectionUtils.isEmpty(entityGuids)) {
                  throw new AtlasBaseException(AtlasErrorCode.INVALID_PARAMETERS, "empty guid list");
              }
  
              entitiesStore.addClassification(entityGuids, classification);
          } finally {
              AtlasPerfTracer.log(perf);
          }
      }
docs: Bulk API to associate a tag to multiple entities