private Collection<Map<String, Map<String, PropertyUpdater>>> addOozieServerHAUpdaters(Collection<Map<String, Map<String, PropertyUpdater>>> updaters) {
    Collection<Map<String, Map<String, PropertyUpdater>>> highAvailabilityUpdaters =
      new LinkedList<>();

    // always add the statically-defined list of updaters to the list to use
    // in processing cluster configuration
    highAvailabilityUpdaters.addAll(updaters);

    // add the updaters for the Oozie HA properties not defined in stack, but
    // required to be present/updated in oozie-site
    highAvailabilityUpdaters.add(createMapOfOozieServerHAUpdaters());

    return highAvailabilityUpdaters;
  }
Creates a Collection of PropertyUpdater maps that include the OozieServer HA properties, and
  adds these to the list of updaters used to process the cluster configuration.
  This new Collection includes the statically-defined updaters,
  in addition to the HA-related updaters.

@param updaters a Collection of updater maps to be included in the list of updaters for
                  this cluster config update
@return A Collection of PropertyUpdater maps to handle the cluster config update
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/BlueprintConfigurationProcessor.java