This logic for iterating over all online players to play a sound is duplicated in PlayerQuitMessageController.java (lines 46-48) and ChatManagerController.java (lines 115-117). To improve maintainability and adhere to the DRY (Don't Repeat Yourself) principle, I suggest extracting this into a shared service, for example, a SoundService.

This would centralize the sound playing logic, making it easier to manage and modify in the future. Here's an example of how such a service could look:

@Service
public class SoundService {
    private final Server server;

    @Inject
    public SoundService(Server server) {
        this.server = server;
    }

    public void playSoundToAll(Sound sound, float volume, float pitch) {
        if (sound == null) {
            return;
        }
        for (Player online : this.server.getOnlinePlayers()) {
            online.playSound(online.getLocation(), sound, volume, pitch);
        }
    }
}

You could then inject SoundService into the controllers and simplify the code to a single method call, like this.soundService.playSoundToAll(sound.afterJoin, sound.afterJoinVolume, sound.afterJoinPitch);.

This check if (!this.chatSettings.chatEnabled()) appears to be redundant and might cause unintended behavior. The event handler is already set to ignoreCancelled = true, so it won't run if the chat event is cancelled (for example, when chat is disabled for a user without bypass permissions).

However, for a user with bypass permissions, their message will go through, but this check will prevent the sound from playing. It seems more consistent to play the sound if the message is successfully sent. I recommend removing this conditional block to fix this.