fuckn piece of code

package me.bacon.plugin;

import java.util.logging.Logger;

import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.enchantments.Enchantment;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.inventory.ClickType;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.inventory.InventoryMoveItemEvent;
import org.bukkit.event.inventory.InventoryType.SlotType;
import org.bukkit.inventory.InventoryHolder;
import org.bukkit.inventory.ItemStack;
import org.bukkit.plugin.PluginDescriptionFile;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.potion.PotionEffect;
import org.bukkit.potion.PotionEffectType;

public class Main extends JavaPlugin implements Listener{
	Logger logger = getLogger();
	public static Main plugin;

	public void onDisable() {
		PluginDescriptionFile pdfFile = this.getDescription();
		this.logger.info(pdfFile.getName() + " Has been disabled!");
	}

	public void onEnable() {
		plugin = this;
		PluginDescriptionFile pdfFile = this.getDescription();
		this.logger.info(pdfFile.getName() + " Version: "
				+ pdfFile.getVersion() + " Has been Enabled!");
		PluginManager pm = getServer().getPluginManager();
		pm.registerEvents(this, this);
		getConfig().options().copyDefaults(true);
		saveConfig();
	}

	@EventHandler
	public void onInventoryClick(InventoryClickEvent e) {
		ItemStack current = e.getCurrentItem();
		ItemStack cursor = e.getCursor();
		if(e.getSlotType() == SlotType.ARMOR){
			 if (current != null && current.getItemMeta() != null && current.getItemMeta().getDisplayName() != null)
				 potion(e.getInventory().getHolder(), current);
			else if (cursor != null && cursor.getItemMeta() != null && cursor.getItemMeta().getDisplayName() != null)
				potion(e.getInventory().getHolder(), cursor);
      } else if(e.getClick().isShiftClick()){
			 if (current != null && current.getItemMeta() != null && current.getItemMeta().getDisplayName() != null)
				 potion(e.getInventory().getHolder(), current);
      } else if (e.getClick().isRightClick()){
			 if (current != null && current.getItemMeta() != null && current.getItemMeta().getDisplayName() != null)
				 potion(e.getInventory().getHolder(), current);
      }
		}


	private void potion(InventoryHolder holder, ItemStack item) {
		if(item.getItemMeta().getDisplayName().equals(ChatColor.GOLD + "Basic Mining Helmet")){
			if (holder instanceof Player){
				System.out.println("is player");
				Player p = (Player) holder;
				if (p.getInventory().getHelmet() == null || p.getInventory().getHelmet().getType() == Material.AIR) {
					//p.sendMessage("Adding potion...");
					p.addPotionEffect(new PotionEffect(PotionEffectType.NIGHT_VISION, Integer.MAX_VALUE, 0));
				} else {
					//p.sendMessage("Removing potion...");
					p.removePotionEffect(PotionEffectType.NIGHT_VISION);
				}
      }
		}
	}
}