@Override
  public int hashCode() {
    int result = artifactId != null ? artifactId.hashCode() : 0;
    result = 31 * result + (groupId != null ? groupId.hashCode() : 0);
    result = 31 * result + (version != null ? version.hashCode() : 0);
    result = 31 * result + (classifier != null ? classifier.hashCode() : 0);
    result = 31 * result + (extension != null ? extension.hashCode() : 0);
    result = 31 * result + (properties != null ? properties.hashCode() : 0);
    return result;
  }
@Override
  public int hashCode()