public String waitOnMaster(int serverNumber) {
    JVMClusterUtil.MasterThread masterThread = this.masterThreads.get(serverNumber);
    return waitOnMaster(masterThread);
  }
Wait for the specified master to stop. Removes this thread from list of running threads.
@return Name of master that just went down.
hbase-server/src/main/java/org/apache/hadoop/hbase/LocalHBaseCluster.java