#vulnerable code 
                                @Override
    public void execute(CommandSender sender, String[] args) {
        MessagesConfig messages = Messages.getInstance();

        if (args.length < 1) {
            sender.sendMessage(messages.generalNoTagGiven);
            return;
        }

        if (!GuildUtils.tagExists(args[0])) {
            sender.sendMessage(messages.generalNoGuildFound);
            return;
        }

        Guild guild = GuildUtils.byTag(args[0]);
        GuildUtils.deleteGuild(guild);
        sender.sendMessage(messages.deleteSuccessful.replace("{GUILD}", guild.getName()).replace("{TAG}", guild.getTag()));

        Player owner = guild.getOwner().getPlayer();
        if (owner != null) {
            owner.sendMessage(messages.adminGuildBroken.replace("{ADMIN}", sender.getName()));
        }

        Bukkit.getServer().broadcastMessage(messages.broadcastDelete.replace("{PLAYER}", sender.getName()).replace("{GUILD}", guild.getName()).replace("{TAG}", guild.getTag()));
    } 
                            #location 17 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public void execute(CommandSender sender, String[] args) {
        MessagesConfig messages = Messages.getInstance();

        if (args.length < 1) {
            sender.sendMessage(messages.generalNoTagGiven);
            return;
        }

        Guild guild = GuildUtils.byTag(args[0]);

        if (guild == null) {
            sender.sendMessage(messages.generalNoGuildFound);
            return;
        }

        GuildUtils.deleteGuild(guild);
        Player owner = guild.getOwner().getPlayer();

        MessageTranslator translator = new MessageTranslator()
                .register("{GUILD}", guild.getName())
                .register("{TAG}", guild.getTag())
                .register("{ADMIN}", sender.getName())
                .register("{PLAYER}", sender.getName());

        if (owner != null) {
            owner.sendMessage(translator.translate(messages.adminGuildBroken));
        }

        sender.sendMessage(translator.translate(messages.deleteSuccessful));
        Bukkit.getServer().broadcastMessage(translator.translate(messages.broadcastDelete));
    }