luckpermstest.java

public final class LuckPermsIntergrationTest extends JavaPlugin {
	private static LuckPermsApi luckPermsApi;

	@Override
	public void onEnable() {
		RegisteredServiceProvider<LuckPermsApi> provider = Bukkit.getServicesManager().getRegistration(LuckPermsApi.class);
		if (provider != null) {
			setLuckPermsApi(provider.getProvider());
		}
		// Plugin startup logic

	}

	@Override
	public void onDisable() {
		// Plugin shutdown logic
	}
  
  public void rankup(Player player, String rankupGroup) {
    String currentGroup = luckPermsApi.getUser(player.getUniqueId()).getPrimaryGroup();
    //your rankup logic here
  }
}

}