@Override
  public Set<String> getVersions(final String groupId, final String artifactId) {
    String ga = groupId + ":" + artifactId;
    return doIndexTask(() -> notNullize(myData.groupWithArtifactToVersionMap.get(ga)), Collections.emptySet());
  }
@Override
  public Set<String> getVersions(final String groupId, final String artifactId)