@Override
  public Map<String, Entry<Long, Long>> getNamespaceSpaceUtilization() {
    QuotaObserverChore quotaChore = master.getQuotaObserverChore();
    if (quotaChore == null) {
      return Collections.emptyMap();
    }
    Map<String, SpaceQuotaSnapshot> namespaceSnapshots = quotaChore.getNamespaceQuotaSnapshots();
    Map<String, Entry<Long, Long>> convertedData = new HashMap<>();
    for (Entry<String, SpaceQuotaSnapshot> entry : namespaceSnapshots.entrySet()) {
      convertedData.put(entry.getKey(), convertSnapshot(entry.getValue()));
    }
    return convertedData;
  }
Impl for exposing HMaster Information through JMX
hbase-server/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterWrapperImpl.java