Answers for "bukkit disable fire spreading"

spigot disable join message

@EventHandler
public void onJoin(PlayerJoinEvent e) {
  e.setJoinMessage("");
}

spigot disable health regeneration

@EventHandler
    public void onPlayerRegainHealth(EntityRegainHealthEvent event) {
        if(event.getRegainReason() == RegainReason.SATIATED || event.getRegainReason() == RegainReason.REGEN)
            event.setCancelled(true);
    }