not working gui code

import java.awt.Menu;
import java.util.ArrayList;
import java.util.List;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.enchantments.Enchantment;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.PlayerInventory;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.plugin.java.JavaPlugin;

public class Kits extends JavaPlugin implements Listener {


	public void onEnable() {
		Bukkit.getServer().getPluginManager().registerEvents(this, this);
		Bukkit.getServer().getLogger().info("Kits v1.0 has been enabled!");
	}
	public void onDisable() {
		Bukkit.getServer().getLogger().info("Kits v1.0 has been disabled.");
	}

	public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args) {
		if(!(sender instanceof Player)) {
			sender.sendMessage(ChatColor.RED + " The console cannot use this command!");
		}
		//Player player = (Player) sender;




		return true;
	}

	private void onGUI(Player player) {
		Inventory inv = Bukkit.createInventory(null, 9, ChatColor.GOLD + "Class chooser");

		ItemStack miner = new ItemStack(Material.DIAMOND_PICKAXE);
		ItemMeta minermeta = miner.getItemMeta();


		minermeta.setDisplayName(ChatColor.DARK_GREEN + "The Miner class!");
		miner.setItemMeta(minermeta);

		inv.setItem(5, miner);

		player.openInventory(inv);
	}


	@EventHandler
	public void onPlayerJoin(PlayerJoinEvent e) {

		//see if they're new
		PlayerInventory pi = e.getPlayer().getInventory();


		if(getConfig().getConfigurationSection(getName()) == null) {
			//add the kit cause they're new
			ItemStack ironpick = new ItemStack(Material.IRON_PICKAXE, 1);
			ironpick.addEnchantment(Enchantment.DURABILITY, 3);
			ItemMeta ironpickmeta = ironpick.getItemMeta();
			ironpickmeta.setDisplayName(ChatColor.LIGHT_PURPLE + "Miner's Pickaxe");
			List<String> lore = new ArrayList<String>();
			lore.add(ChatColor.BLUE + "This pickaxe will take");
			lore.add(ChatColor.BLUE + "you through the");
			lore.add(ChatColor.GOLD + "deepest " + ChatColor.BLUE + "of caves!");
			ironpickmeta.setLore(lore);
			ironpick.setItemMeta(ironpickmeta);
			pi.addItem(ironpick);
			getConfig().createSection(getName());
			saveConfig();
			pi.addItem(new ItemStack(Material.WORKBENCH, 1));

		}

	}

	@EventHandler
	public void onPlayerInteract(PlayerInteractEvent e) {
		Action a = e.getAction();
		ItemStack is = e.getItem();

		if(a == Action.PHYSICAL || is == null || is.getType() == Material.AIR)
			return;
		if(is.getType() == Material.WORKBENCH) {
			onGUI(e.getPlayer());
		}
	}

	@EventHandler
	public void onInventoryClick(InventoryClickEvent e) {
		if(e.getInventory().getName()
				.equalsIgnoreCase("Class Chooser")) {

			Player player = (Player) e.getWhoClicked();
			e.setCancelled(true);

			if(e.getCurrentItem() == null || e.getCurrentItem().getType() == Material.AIR || !e.getCurrentItem().hasItemMeta()) {
				player.closeInventory();
				return;
			}
			switch(e.getCurrentItem().getType()) {
			case WORKBENCH:
				//add kit
				player.sendMessage(ChatColor.BLUE + "You got your kit!");
				break;
			default:
			player.closeInventory();
			break;
			}
		}
	}




}