private static Artifact @Nullable [] getDownloadServiceVersions(@NotNull String id) {
    final URL url = createVersionsUrl(id);
    if (url == null) return null;
    final Artifacts allArtifacts = deserialize(url);
    return allArtifacts == null ? null : allArtifacts.getArtifacts();
  }
private static Artifact @Nullable [] getDownloadServiceVersions(@NotNull String id)