public List<RegionInfo> getSystemRegionInfoList() {
    return regions.stream().filter(RegionStateNode::isSystemTable)
      .map(RegionStateNode::getRegionInfo).collect(Collectors.toList());
  }
State of Server; list of hosted regions, etc.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/ServerStateNode.java