public Optional<ApplicationData> applicationData(ApplicationId id) {
        Optional<byte[]> data = curator.getData(applicationPath(id));
        if (data.isEmpty() || data.get().length == 0) return Optional.empty();

        try {
            return Optional.of(ApplicationData.fromBytes(data.get()));
        } catch (IllegalArgumentException e) {
            return applicationDataOldFormat(id);
        }
    }
Returns application data for the given application.
Returns Optional.empty() if application not found or no application data exists.
configserver/src/main/java/com/yahoo/vespa/config/server/application/ApplicationCuratorDatabase.java