code: public List<RESTLayer> getAllImportedLayers(Integer importJobId, List<RESTImportTask> tasks) throws Exception {
          ArrayList<RESTLayer> layers = new ArrayList<RESTLayer>();
          for (RESTImportTask task : tasks) {
  
              RESTImportTask refreshedTask = this.getRESTImportTask(importJobId, task.getId());
              if (refreshedTask.getState().equalsIgnoreCase("COMPLETE")) {
                  Response httpResponse = HttpUtil.get(
                      this.addEndPoint(importJobId + "/tasks/" + task.getId() + "/layer"),
                      this.username,
                      this.password
                  );
                  RESTLayer layer = (RESTLayer) this.asEntity(httpResponse.getBody(), RESTLayer.class);
  
                  if (layer != null) {
                      layers.add(layer);
                  }
              } else if ((tasks.size() == 1) && refreshedTask.getState().equalsIgnoreCase("ERROR")) {
                  throw new GeoServerRESTImporterException(refreshedTask.getErrorMessage());
              }
          }
          return layers;
      }
docs: fetch all created Layers of import job