Possible NPE on fallbackCredentials in PluginUserSession

if (session == null) {
            Main main = (Main)Application.get();
            if (fallbackCredentials == null) {
                try {
                    main.getRepository(); // side effect of reinitializing fallback credentials
                } catch (RepositoryException ignored) {
                }
            }
            if (fallbackSession == null) {
                try {
                    fallbackSession = JcrSessionModel.login(fallbackCredentials);
                } catch (RepositoryException e) {
                    log.warn("Cannot login fallback session: " + e.getMessage());
                }
            }