question: @ Deprecated public void updateClusterState ( ) throws KeeperException , InterruptedException { synchronized ( getUpdateLock ( ) ) { if ( clusterState == null ) { createClusterStateWatchersAndUpdate ( ) ; return ; } refreshCollectionList ( null ) ; refreshLiveNodes ( null ) ; refreshLegacyClusterState ( null ) ; Collection < String > safeCopy = new ArrayList < > ( watchedCollectionStates . keySet ( ) ) ; Set < String > updatedCollections = new HashSet < > ( ) ; for ( String coll : safeCopy ) { DocCollection newState = fetchCollectionState ( coll , null ) ; if ( updateWatchedCollection ( coll , newState ) ) { updatedCollections . add ( coll ) ; } } constructState ( updatedCollections ) ; } }
target:  Forcibly refresh cluster state from ZK. Do this only to avoid race conditions because it's expensive.