public static void closeAll() {
    LOG.debug("Closing all handles");
    synchronized (lock) {
      Iterator<Map.Entry<String, List<Connection>>> itr = connectionMap.entrySet().iterator();
      Map.Entry<String, List<Connection>> connHandle = null;
      while (itr.hasNext()) {
        connHandle = itr.next();
        closeConnections(connHandle.getKey(), connHandle.getValue());
        itr.remove();
      }
    }
  }
Close all outstanding connections created by getSplits() calls
llap-ext-client/src/java/org/apache/hadoop/hive/llap/LlapBaseInputFormat.java