code: @Override
    public String getOrCreateForKey(String key) {
      return uuidsByDbKey.computeIfAbsent(key, k1 -> uuidsByMigratedKey.computeIfAbsent(k1, k2 -> Uuids.create()));
    }
docs: Get UUID from component having the same key in database if it exists, otherwise look for migrated keys, and finally generate a new one.