@Override public synchronized void saveProperties(String mapKey, PropertyMap map) {
    UUID digest = map.getDigest();
    byte[] data = serialize(map);
    digests.put(mapKey, digest);
    properties.put(mapKey, data);
    map.setClean();
  }
The digests for the stored maps.
standalone-metastore/metastore-common/src/test/java/org/apache/hadoop/hive/metastore/properties/TransientPropertyStore.java