@VisibleForTesting
  public <K extends Serializable, T extends Serializable> T get(String columnFamilyName, K key) {
    Preconditions.checkArgument(!closed);
    try {
      Preconditions.checkArgument(key != null, "keys in rocksdb can not be null!");
      byte[] val =
          rocksDB.get(handleMap.get(columnFamilyName), SerializationUtil.kryoSerialize(key));
      return val == null ? null : SerializationUtil.kryoDeserialize(val);
    } catch (Exception e) {
      throw new AmoroIOException(e);
    }
  }
Retrieve a value for a given key in a column family.

@param columnFamilyName Column Family Name
@param key Key to be retrieved
amoro-format-iceberg/src/main/java/org/apache/amoro/utils/map/RocksDBBackend.java