if(ping_input != null) { try { ping_input.close(); } catch(Exception ex) { } ping_input=null; }
Util.close(ping_input); ping_input=null;
    void teardownPingSocket() {        synchronized(sock_mutex) {            if(ping_sock != null) {                try {                    ping_sock.shutdownInput();                    ping_sock.close();                }                catch(Exception ex) {                }                ping_sock=null;            }            if(ping_input != null) {                try {                    ping_input.close();                }                catch(Exception ex) {                }                ping_input=null;            }        }    }