if(client_sock != null) { try { client_sock.close(); } catch(Exception ex) { } client_sock=null; }
Util.close(client_sock); client_sock=null;
        void closeClientSocket() {            synchronized(mutex) {                if(client_sock != null) {                    try {                        client_sock.close();                    }                    catch(Exception ex) {                    }                    client_sock=null;                }            }        }