private Connection randomGet(List<Connection> connections) {
        if (null == connections || connections.isEmpty()) {
            return null;
        }

        int size = connections.size();
        int tries = 0;
        Connection result = null;
        while ((result == null || !result.isFine()) && tries++ < MAX_TIMES) {
            result = connections.get(ThreadLocalRandom.current().nextInt(size));
        }

        if (result != null && !result.isFine()) {
            result = null;
        }
        return result;
    }
get one connection randomly

@param connections source connections
@return result connection
src/main/java/com/alipay/remoting/RandomSelectStrategy.java