#vulnerable code 
                                public Channel getChannel(String clientName) {
        if (log.isDebugEnabled()) {
            for (Map.Entry<String, List<Channel>> entry : channelMap.entrySet()) {
                log.debug("participantName={}, channelNum={}",
                        entry.getKey(),
                        entry.getValue() == null ? 0 : entry.getValue().size());
            }
        }
        lock.readLock().lock();
        try {
            List<Channel> channelList = channelMap.get(clientName);
            if (channelList == null || channelList.size() == 0) {
                log.info("no available connection for clientName={}", clientName);
                return null;
            }
            int id = index.getAndIncrement() % channelList.size();
            Channel channel = channelList.get(id);
            return channel;
        } finally {
            lock.readLock().unlock();
        }
    } 
                            #location 3 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                public Channel getChannel(String clientName) {
        if (log.isDebugEnabled()) {
            for (Map.Entry<String, List<Channel>> entry : innerStoreManager.getChannelMap().entrySet()) {
                log.debug("participantName={}, channelNum={}",
                        entry.getKey(),
                        entry.getValue() == null ? 0 : entry.getValue().size());
            }
        }
        lock.readLock().lock();
        try {
            return innerStoreManager.getChannel(clientName);
        } finally {
            lock.readLock().unlock();
        }
    }