It's not just the visible complexity in this one file. The point of it is to keep a subscriber count in sync, but you have that code I referenced above, plus:

LinkPersonCommunityCreatedEvent LinkPersonCommunityDeletedEvent LinkPersonCommunityCreatedPublisher LinkPersonCommunityDeletedPublisher

And then there are things like LinkPersonCommunityUpdated[Event/Publisher] which don't even seem to be used.

This is all boilerplate IMO.

And all of that only (currently) serves keeping that subscriber count up to date.

And then there's the hidden complexity of how things get wired up with spring.

And after all that it's still fragile because that event is not tied to object creation:

  @Transactional
  public void addLink(Person person, Community community, LinkPersonCommunityType type) {

    final LinkPersonCommunity newLink = LinkPersonCommunity.builder().community(community)
        .person(person).linkType(type).build();
    person.getLinkPersonCommunity().add(newLink);
    community.getLinkPersonCommunity().add(newLink);
    linkPersonCommunityRepository.save(newLink);
    linkPersonCommunityCreatedPublisher.publish(newLink);
  }

And there's some code here:

https://github.com/sublinks/sublinks-api/blob/main/src/main/java/com/sublinks/sublinksapi/api/lemmy/v3/community/controllers/CommunityOwnerController.java#L138C31-L138C50

    final Set<LinkPersonCommunity> linkPersonCommunities = new LinkedHashSet<>();
    linkPersonCommunities.add(LinkPersonCommunity.builder().community(community).person(person)
        .linkType(LinkPersonCommunityType.owner).build());
    linkPersonCommunities.add(LinkPersonCommunity.builder().community(community).person(person)
        .linkType(LinkPersonCommunityType.follower).build());

    communityService.createCommunity(community);

    linkPersonCommunityRepository.saveAllAndFlush(linkPersonCommunities);

that is able to bypass the community link service and create links in the repository directly, which would presumably not trigger than event.

Maybe there's a good reason for that, but it sure looks fragile to me.