Errors retrieving itemstacks from config. I can save itemstacks but not read them.

Hello,

The purpose of this plugin is virtual chests. A player runs /vc and they can store their items similar to how an ender chest works. I will paste my code and the error that comes up when I run it.

Code:

package io.github.**********.VChestReloaded;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map.Entry;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.ItemStack;
import org.bukkit.plugin.java.JavaPlugin;

public class VChestReloaded extends JavaPlugin {
    HashMap<Player, Inventory> inventories = new HashMap<Player, Inventory>();
  
    @Override
    public void onEnable() {
        getLogger().info("VChestReloaded started");
      
        // read config values in to inventories HashMap
      
    }
  
    public void writeInventory(Player P) {
        for (int i = 0; i < inventories.get(P).getSize(); i++)  {
            ItemStack currentItem = inventories.get(P).getItem(i);
            // itemList.add(currentItem);
            getConfig().set(P.getName() + "." + i, currentItem);;
        }
    }
  
    public void readInventory(Player P) {
        // this should update the hashmap with the most recent values stored in the config
        List<ItemStack> items = new ArrayList<ItemStack>();
      
        int counter = 0;
        for (int i = 0; i < getConfig().getList(P.getName()).size(); i++) {
            items.add(((ItemStack) getConfig().getList(P.getName()).get(counter)));
            counter++;
        }

        Inventory inv = Bukkit.createInventory(null, 54);
        inv.setStorageContents((ItemStack[]) items.toArray());
      
        inventories.put(P, inv);
    }
  
    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
        Player P = (Player) sender;
      
        if (cmd.getName().equalsIgnoreCase("vc")) {
            P.sendMessage(ChatColor.GRAY + "Opening VChest.");
          
            if (inventories.get(P) != null) {
                readInventory(P);
              
                P.openInventory(inventories.get(P));
              
                writeInventory(P);
                saveConfig();
                reloadConfig();
                return true;
              
            } else {
                // in the case that a player doesn't have a vchest, we will make one
                Inventory inv = Bukkit.createInventory(null, 54, P.getName() + "'s Virtual Chest");
                inventories.put(P, inv);
                P.openInventory(inventories.get(P));
              
                writeInventory(P);
                saveConfig();
                reloadConfig();
              
                getLogger().info("Saved " + P.getName() + " vchest.");
                return true;
            }
        } else if (cmd.getName().equalsIgnoreCase("getinventories")) {
            for (Entry<Player, Inventory> entry : inventories.entrySet()) {
                P.sendMessage(entry.getKey().getName() + " : " + entry.getValue().getSize());
                return true;
            }
        }
      
        return true;
    }
  
    @Override
    public void onDisable() {
        getLogger().info("VChestReloaded stopped");
    }
  
}

Error:

Code:

org.bukkit.command.CommandException: Unhandled exception executing command 'vc' in plugin VChestReloaded v1
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:138) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at org.bukkit.craftbukkit.v1_13_R2.CraftServer.dispatchCommand(CraftServer.java:682) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.PlayerConnection.handleCommand(PlayerConnection.java:1579) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.PlayerConnection.a(PlayerConnection.java:1439) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.PacketPlayInChat.a(SourceFile:37) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.PacketPlayInChat.a(SourceFile:9) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.PlayerConnectionUtils.a(SourceFile:10) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:514) [?:?]
        at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
        at net.minecraft.server.v1_13_R2.SystemUtils.a(SourceFile:199) [craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.MinecraftServer.b(MinecraftServer.java:838) [craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.DedicatedServer.b(DedicatedServer.java:382) [craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.MinecraftServer.a(MinecraftServer.java:791) [craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at net.minecraft.server.v1_13_R2.MinecraftServer.run(MinecraftServer.java:694) [craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        at java.lang.Thread.run(Thread.java:844) [?:?]
Caused by: java.lang.NullPointerException
        at io.github.**********.VChestReloaded.VChestReloaded.readInventory(VChestReloaded.java:41) ~[?:?]
        at io.github.**********.VChestReloaded.VChestReloaded.onCommand(VChestReloaded.java:60) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[craftbukkit-1.13.2.jar:git-Bukkit-a5b9c7b]
        ... 15 more

When I run it without using readInventory() to get the itemstacks, the plugin works, but it resets the hashmap on a reload. I want to read and write to the config every time a player uses this command. But I can't read from the config every time, as it throws this error. Only can write. When it works, this is what the config looks like:

Code:

airpod_salesman:
  '0':
    ==: org.bukkit.inventory.ItemStack
    v: 1631
    type: COBBLESTONE
    amount: 32
  '1':
    ==: org.bukkit.inventory.ItemStack
    v: 1631
    type: COBBLESTONE
    amount: 32

With the error causing readInventory(), the config simply looks like this:

Code:

airpod_salesman: {}

Please comment if you have any questions to ask about it. I have been pulling my hair out from 2 AM to 5 AM trying to fix this one bug and none of my solutions work.

Regards

 

I know it has GetItemStack, I use the Java docs for bukkit. Using GetItemStack did not work in the numerous ways I tried it.

I don't care about the UUID issue at the moment, just want to build this prototype.