@Override
  public void init(ByteArrayRef bytes, int start, int length) {
    LazyBinaryUtils.readVLong(bytes.getData(), start, vLong);
    assert (length == vLong.length);
    data.set(vLong.value);
  }
The reusable vLong for decoding the long.
serde/src/java/org/apache/hadoop/hive/serde2/lazybinary/LazyBinaryLong.java