Provider

package me.LobbyBrain.Inventory;

import java.util.List;

import org.bukkit.Material;
import org.bukkit.entity.Player;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;

import fr.minuskube.inv.ClickableItem;
import fr.minuskube.inv.content.InventoryContents;

public class InventoryProvider implements fr.minuskube.inv.content.InventoryProvider{

    private List<String> items;
    private List<String> displayname;
    private int i;
    private int i2;
    SetupPlugin sp = new SetupPlugin();
    InventoryMain im = new InventoryMain();
    @Override
    public void init(Player player, InventoryContents contents) {

    }

    @Override
    public void update(Player player, InventoryContents contents) {
        InventoryElements(player, contents);
    }

    @SuppressWarnings("static-access")
    public void InventoryElements(Player player, InventoryContents contents) {
        for(String itemkey : sp.plugin.getMenuFile().getConfigurationSection("LobbyBrain.Menus."+im.inventory+".Items").getKeys(false)) {
            items = sp.plugin.getMenuFile().getStringList("LobbyBrain.Menus."+im.inventory+".Items."+itemkey+".ID");
            displayname = sp.plugin.getMenuFile().getStringList("LobbyBrain.Menus."+im.inventory+".Items."+itemkey+".DisplayName");
            ItemStack stack = new ItemStack(Material.valueOf(items.get(i)));
            ItemMeta meta = stack.getItemMeta();
            meta.setDisplayName(displayname.get(i2));
            stack.setItemMeta(meta);
            contents.set(
                    sp.plugin.getMenuFile().getInt("LobbyBrain.Menus."+im.inventory+".Items."+itemkey+".Y"),
                    sp.plugin.getMenuFile().getInt("LobbyBrain.Menus."+im.inventory+".Items."+itemkey+".X"),
                    ClickableItem.of(stack, e ->{
                        if(sp.plugin.getMenuFile().getString("LobbyBrain.Menus."+im.inventory+".Items."+itemkey+".SLOT-TYPE").contains("INV-OPEN")) {
                            InventoryMain.INV().close(player);
                            im.inventory = sp.plugin.getMenuFile().getConfigurationSection("LobbyBrain.Menus."+im.inventory+".Items."+itemkey).getString("OPEN-INV");
                            InventoryMain.INV2().open(player);
                            return;
                        }
                    }));
            }
        if(i < items.size() -1) {
            i++;
        }else {
            i = 0;
        }
        if(i2 < displayname.size() -1) {
            i2++;
        }else {
            i2 = 0;
        }
    }
}