#fixed code
                                private void send(InternalMessage message, int retry) {
        if (message.getSignal() != Signal.PING) {
            log.debug("Outgoing: " + message.transformToExternalMessage());
        }
        if (message.getSignal() == Signal.ERROR) {
            tryToSendErrorMessage(message);
            return;
        }
        Member destination = message.getTo();
        if (destination == null || !destination.getSession().isOpen()) {
            log.warn("Destination member is not set or session is closed! Message will not be send: " + message.transformToExternalMessage());
            return;
        }
        members.findBy(destination.getId()).ifPresent(member ->
                lockAndRun(message, member, retry)
        );
    }
#vulnerable code 
                                private void send(InternalMessage message, int retry) {
        Message messageToSend = message.transformToExternalMessage();
        if (message.getSignal() != Signal.PING) {
            log.info("Outgoing: " + toString());
        }
        Session destSession = message.getTo().getSession();
        if (!destSession.isOpen()) {
            log.warn("Session is closed! Message will not be send: ");
            return;
        }
        try {
            RemoteEndpoint.Basic basic = destSession.getBasicRemote();
            synchronized (basic) {
                basic.sendObject(messageToSend);
            }
        } catch (Exception e) {
            if (retry >= 0) {
                log.info("Retrying... " + messageToSend);
                send(message, --retry);
            }
            log.error("Unable to send message: " + messageToSend + " error during sending!");
            throw new RuntimeException("Unable to send message: " + messageToSend, e);
        }
    } 
                            #location 6 
                            #vulnerability type NULL_DEREFERENCE