public ApplicationVersions ensureApplicationLoaded(RemoteSession session) {
        if (session.applicationVersions().isPresent()) {
            return session.applicationVersions().get();
        }
        Optional<Long> activeSessionId = getActiveSessionId(session.getApplicationId());
        Optional<ApplicationVersions> previousActiveApplicationVersions = activeSessionId.filter(session::isNewerThan)
                                                                         .flatMap(this::activeApplicationVersions);
        ApplicationVersions applicationVersions = loadApplication(session, previousActiveApplicationVersions);
        RemoteSession activated = session.activated(applicationVersions);
        long sessionId = activated.getSessionId();
        remoteSessionCache.put(sessionId, activated);
        updateSessionStateWatcher(sessionId);

        return applicationVersions;
    }
A session for which we don't have a watcher, i.e. hitherto unknown to us.

@param sessionId session id for the new session
configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java