@Override
  public int hashCode() {
    if (!hashCodeValid) {
      throw new RuntimeException("Cannot get hashCode() from deserialized "
          + HiveKey.class);
    }
    return hashCode;
  }
HiveKey is a simple wrapper on Text which allows us to set the hashCode
easily. hashCode is used for hadoop partitioner.
ql/src/java/org/apache/hadoop/hive/ql/io/HiveKey.java