Class to easily serialize ItemStacks for the Bukkit API - https://www.spigotmc.org/threads/serializableitemstack-as-easy-as-it-should-be-by-default.208834/

SerializableItemStack.java

package github.scarsz;

import org.bukkit.Material;
import org.bukkit.configuration.serialization.ConfigurationSerialization;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;
import org.yaml.snakeyaml.DumperOptions;
import org.yaml.snakeyaml.Yaml;

import java.util.HashMap;
import java.util.Map;

/**
 * Made by Scarsz
 * http://github.com/Scarsz
 *
 * @in /dev/hell
 * @on 1/13/2017
 */
public class SerializableItemStack {

    private Map<String, Map<String, Object>> serializableMap = new HashMap<>();
    private static Yaml yaml;
    static {
        DumperOptions dumperOptions = new DumperOptions();
        dumperOptions.setPrettyFlow(true);
        yaml = new Yaml(dumperOptions);
    }

    public SerializableItemStack(ItemStack itemStackToMakeSerializable) {
        ItemStack itemStack = itemStackToMakeSerializable.clone();

        if (itemStack == null) itemStack = new ItemStack(Material.AIR);
        serializableMap.put("itemMeta", itemStack.hasItemMeta() ? itemStack.getItemMeta().serialize() : null);
        itemStack.setItemMeta(null);
        serializableMap.put("itemStack", itemStack.serialize());
    }
    public SerializableItemStack(Map<String, Map<String, Object>> serializableMap) {
        this.serializableMap = serializableMap;
    }
    public SerializableItemStack(String yamlSerializedMap) {
        this.serializableMap = yaml.loadAs(yamlSerializedMap, Map.class);
    }

    public ItemStack toItemStack() {
        ItemStack itemStack = ItemStack.deserialize(serializableMap.get("itemStack"));
        if (serializableMap.get("itemMeta") != null) itemStack.setItemMeta((ItemMeta) ConfigurationSerialization.deserializeObject(serializableMap.get("itemMeta"), ConfigurationSerialization.getClassByAlias("ItemMeta")));
        return itemStack;
    }
    public Map<String, Map> toSerializableMap() {
        return new HashMap<>(serializableMap);
    }
    public String toYaml() {
        return yaml.dump(serializableMap);
    }

}