@Override
  public synchronized Set getRootRegionNames() {
    if (rootRegionNames == null) {
      return null;
    } else {
      return new TreeSet(Arrays.asList(rootRegionNames));
    }
  }
For use only by DataExternalizable mechanism
geode-core/src/main/java/org/apache/geode/internal/admin/remote/RemoteCacheInfo.java