private void validateProcessorConfiguration(Set<String> stores, Map<String, SideInputsProcessor> storeToProcessor) {
    stores.forEach(storeName -> {
      if (!storeToProcessor.containsKey(storeName)) {
        throw new SamzaException(
            String.format("Side inputs processor missing for store: %s.", storeName));
      }
    });
  }
Validates that each store has an associated {@link SideInputsProcessor}
samza-core/src/main/java/org/apache/samza/storage/TaskSideInputHandler.java