@Nullable
  public static DependencyConflictId create(String groupId, String artifactId, String type, String classifier) {
    if (StringUtil.isEmpty(groupId)) return null;
    if (StringUtil.isEmpty(artifactId)) return null;

    return new DependencyConflictId(groupId, artifactId, type, classifier);
  }
@Nullable
  public static DependencyConflictId create(String groupId, String artifactId, String type, String classifier)