code: private void executeUpdatesAsynchronous(DBTransaction transaction) {
          Collection<BoundStatement> mutations = getMutations(transaction);
          List<ResultSetFuture> futureList = new ArrayList<>(mutations.size());
          for(BoundStatement mutation: mutations) {
              ResultSetFuture future = m_dbservice.getSession().executeAsync(mutation);
              futureList.add(future);
          }
          m_logger.debug("Waiting for {} asynchronous futures", futureList.size());
          for (ResultSetFuture future : futureList) {
              future.getUninterruptibly();
          }
      }
docs: Execute all updates asynchronously and wait for results.