public synchronized ZKWatcher getZooKeeperWatcher() throws IOException {
    if (zooKeeperWatcher == null) {
      zooKeeperWatcher = new ZKWatcher(conf, "testing utility", new Abortable() {
        @Override
        public void abort(String why, Throwable e) {
          throw new RuntimeException("Unexpected abort in HBaseZKTestingUtility:" + why, e);
        }

        @Override
        public boolean isAborted() {
          return false;
        }
      });
    }
    return zooKeeperWatcher;
  }
Returns a ZKWatcher instance. This instance is shared between HBaseTestingUtility instance
users. Don't close it, it will be closed automatically when the cluster shutdowns
@return The ZKWatcher instance.
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/HBaseZKTestingUtility.java