some refactors + better id setting

src/main/java/net/hexa/MythicItems/CommandMythicEssence.java

@@ -0,0 +1,25 @@
+package net.hexa.MythicItems;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+
+import net.hexa.MythicItems.Mythics.RockCracker;
+
+public class CommandMythicEssence implements CommandExecutor {
+
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+        if (sender instanceof Player) {
+            Player player = (Player) sender;
+
+            ItemStack item = new RockCracker().item;
+
+            player.getInventory().addItem(item);
+        }
+
+        return true;
+    }
+}

src/main/java/net/hexa/MythicItems/MythicItems.java

@@ -1,11 +1,13 @@
-package net.hexa.Plugin;
+package net.hexa.MythicItems;
 import org.bukkit.plugin.java.JavaPlugin;
 
 
-public class Plugin extends JavaPlugin {
+public class MythicItems extends JavaPlugin {
     @Override
     public void onEnable() {
         getLogger().info("onEnable is called!");
+        this.getCommand("essence").setExecutor(new CommandMythicEssence());
+        getServer().getPluginManager().registerEvents(new MythicListener(), this);
     }
 
     @Override

src/main/java/net/hexa/MythicItems/MythicListener.java

@@ -0,0 +1,26 @@
+package net.hexa.MythicItems;
+
+import net.hexa.MythicItems.Mythics.MythicItem;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.BlockBreakEvent;
+import org.bukkit.inventory.ItemStack;
+
+public class MythicListener implements Listener {
+
+    @EventHandler
+    public void onBlockBreak(BlockBreakEvent event) {
+        Player player = event.getPlayer();
+
+        ItemStack item = player.getInventory().getItemInMainHand();
+
+        boolean isMythic = MythicItem.isMythic(item);
+
+        if (isMythic) {
+            int mythic_id = MythicItem.getMythicId(item);
+        }
+
+    }
+}

src/main/java/net/hexa/MythicItems/Mythics/Constants.java

@@ -0,0 +1,8 @@
+package net.hexa.MythicItems.Mythics;
+
+import net.hexa.MythicItems.MythicItems;
+import org.bukkit.NamespacedKey;
+
+public class Constants {
+    public static NamespacedKey mythic_key = new NamespacedKey(new MythicItems(), "mythic-id");
+}

src/main/java/net/hexa/MythicItems/Mythics/MythicItem.java

@@ -0,0 +1,28 @@
+package net.hexa.MythicItems.Mythics;
+
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.persistence.PersistentDataContainer;
+import org.bukkit.persistence.PersistentDataType;
+
+public abstract class MythicItem {
+    public ItemStack item;
+
+    public MythicItem() {}
+
+    public static int getMythicId(ItemStack item) {
+        PersistentDataContainer itemData = item.getItemMeta().getPersistentDataContainer();
+
+        return itemData.get(Constants.mythic_key, PersistentDataType.INTEGER);
+    }
+
+    public static boolean isMythic(ItemStack item) {
+        PersistentDataContainer itemData = item.getItemMeta().getPersistentDataContainer();
+
+        return itemData.has(Constants.mythic_key);
+    }
+
+    protected void setMythicId(int id) {
+        PersistentDataContainer itemData = item.getItemMeta().getPersistentDataContainer();
+        itemData.set(Constants.mythic_key, PersistentDataType.INTEGER, id);
+    }
+}

src/main/java/net/hexa/MythicItems/Mythics/RockCracker.java

@@ -0,0 +1,24 @@
+package net.hexa.MythicItems.Mythics;
+
+import org.bukkit.Material;
+import org.bukkit.enchantments.Enchantment;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.persistence.PersistentDataType;
+
+import java.util.Arrays;
+
+public class RockCracker extends MythicItem {
+    public RockCracker() {
+        item = new ItemStack(Material.NETHERITE_PICKAXE);
+
+        item.addUnsafeEnchantment(Enchantment.EFFICIENCY, 9);
+        item.addUnsafeEnchantment(Enchantment.UNBREAKING, 10);
+
+        item.getItemMeta().setUnbreakable(true);
+        item.getItemMeta().setItemName("Rock Cracker");
+        item.getItemMeta().setLore(Arrays.asList("and the land thrashes in furious pain..."));
+        item.getItemMeta().setEnchantable(0);
+
+        setMythicId(1);
+    }
+}

src/main/java/net/hexa/MythicItems/Mythics/Terra.java

@@ -0,0 +1,27 @@
+package net.hexa.MythicItems.Mythics;
+
+import org.bukkit.Material;
+import org.bukkit.enchantments.Enchantment;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+
+import java.util.Arrays;
+
+public class Terra extends MythicItem {
+    public Terra() {
+        item = new ItemStack(Material.NETHERITE_SHOVEL);
+
+        item.addUnsafeEnchantment(Enchantment.EFFICIENCY, 8);
+        item.addUnsafeEnchantment(Enchantment.UNBREAKING, 10);
+
+        ItemMeta meta = item.getItemMeta();
+
+        meta.setUnbreakable(true);
+        meta.setDisplayName("Terra");
+        meta.setLore(Arrays.asList("All will eventually return to Terra."));
+        meta.setEnchantable(0);
+
+        item.setItemMeta(meta);
+        setMythicId(2);
+    }
+}

src/main/resources/plugin.yml

@@ -1,4 +1,9 @@
-name: EconPlugin
+name: MythicItems
 version: 1.0
-main: net.hexa.Plugin.Plugin
+main: net.hexa.MythicItems.MythicItems
-api-version: '1.21.4'
+api-version: '1.21.4'
+
+commands:
+  essence:
+    description: Gives a Mythic Item Essence
+    usage: /<command>