public static boolean removeShutdownHook(Runnable shutdownHook) {
    if (shutdownHook == null || isShutdownInProgress()) {
      return false;
    }
    return MGR.removeShutdownHook(shutdownHook);
  }
Removes a shutdownHook.

@param shutdownHook shutdownHook to remove.
@return TRUE if the shutdownHook was registered and removed,
FALSE otherwise (including when shutdownHook == null)
common/src/java/org/apache/hive/common/util/ShutdownHookManager.java