(Bukkit Plugin Minecraft) Inventory doesn't clear after I choose kit

Question

I was trying to make some kitPvP plugins but then I was faced with a "bug". When I choose the kit(pvp), it gives me the soups but it doesn't clear the previous inventory (that is the spawn inventory default). Here is the code:

public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
    if(!(sender instanceof Player)) {
        sender.sendMessage(ChatColor.RED + "Apenas players podem usar o comando /kit");
        return true;
    }
    Player p = (Player)sender;
    if (args.length == 0) {
        p.sendMessage(ChatColor.RED + "Precisa defenir qual kit voce quer escolher!");
        p.sendMessage(ChatColor.DARK_GRAY + "Comando: " + ChatColor.RED + "/Kit <kit> " + ChatColor.DARK_GRAY + "ou " + ChatColor.RED + "/Kits");
        return true;
    } else {
        if(args[0].equalsIgnoreCase("pvp")) {
            if(p.hasPermission("kit.pvp")) {
                if (KitAPI.getKit(p) == "Nenhum") {
                    KitAPI.PvP(p);
                    p.sendMessage(ChatColor.GREEN + "Voce escolheu o kit PvP");
                    BarAPI.setMessage(p, ChatColor.GREEN + "Voce escolheu o kit PvP", 5);               
                    p.getInventory().clear();
                    return true;
                } else {
                    p.sendMessage(ChatColor.RED + "Voce ja possui um kit!");
                    return true;
                }
            } else {
                p.sendMessage(ChatColor.RED + "Voce nao possui permissao para executar o comando!");
                return true;
            }
        }
        p.sendMessage(ChatColor.DARK_GRAY + "Esse kit " + ChatColor.RED + args[0] + ChatColor.DARK_GRAY + " e invalido!");
    }
    return false;
}

}

Here is the code where is supposted to clear the inventory:

if (KitAPI.getKit(p) == "Nenhum") {
                    KitAPI.PvP(p);
                    p.sendMessage(ChatColor.GREEN + "Voce escolheu o kit PvP");
                    BarAPI.setMessage(p, ChatColor.GREEN + "Voce escolheu o kit PvP", 5);               
                    p.getInventory().clear();
                    return true;