@Override
  public ZooKeeperHiveLock lock(HiveLockObject key, HiveLockMode mode,
      boolean keepAlive) throws LockException {
    return lock(key, mode, keepAlive, false);
  }
@param key
         The object to be locked
@param mode
         The mode of the lock
@param keepAlive
         Whether the lock is to be persisted after the statement Acquire the
         lock. Return null if a conflicting lock is present.
ql/src/java/org/apache/hadoop/hive/ql/lockmgr/zookeeper/ZooKeeperHiveLockManager.java