public ApplicationMetaData getMetaData() {
        return applicationPackage.isPresent()
                ? applicationPackage.get().getMetaData()
                : sessionZooKeeperClient.loadApplicationPackage().getMetaData();
    }
Returns application id read from ZooKeeper. Will return Optional.empty() if not found
configserver/src/main/java/com/yahoo/vespa/config/server/session/Session.java