private void checkTrackerAddr() {
        Iterator<String> ite = availableTrackerServerAddrSet.iterator();
        while (ite.hasNext()) {
            Socket socket = null;
            String addr = ite.next();
            try {
                socket = createSocket(addr);
            }
            catch (Exception e) {
                logger.error(e.getMessage(), e);
                throw new IllegalStateException("address:{" + addr + "} create socket failed!");
            }
            finally {
                if (socket != null && socket.isConnected()) {
                    try {
                        socket.close();
                    }
                    catch (IOException e) {
                        logger.error("socket:{} close failed!", socket);
                    }
                }
            }
        }
    }