@Override
  public String toString() {
    return "StartMiniClusterOption{" + "numMasters=" + numMasters + ", masterClass=" + masterClass
      + ", numRegionServers=" + numRegionServers + ", rsPorts=" + StringUtils.join(rsPorts)
      + ", rsClass=" + rsClass + ", numDataNodes=" + numDataNodes + ", dataNodeHosts="
      + Arrays.toString(dataNodeHosts) + ", numZkServers=" + numZkServers + ", createRootDir="
      + createRootDir + ", createWALDir=" + createWALDir + '}';
  }
Private constructor. Use {@link Builder#build()}.
hbase-server/src/test/java/org/apache/hadoop/hbase/StartTestingClusterOption.java