java hostname 추출

public static String getLocalHostName(){
    String hostname = System.getenv("HOSTNAME");
    if(hostname != null) {
      return hostname;
    }

    String lineStr = "";
    try {
        Process process = Runtime.getRuntime().exec("hostname");
        BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream()));
        while((lineStr = br.readLine()) != null ){
            hostname = lineStr;
        }
    }catch (IOException e) {
        e.printStackTrace();
        hostname = null;
    }
    return hostname;
  }