Removing an item from an inventory

My plugins work like they use a diamond (right click) to give them a boost, but i need help making it so that the diamond disappears after they right click it.

Code:java

public class effects
  extends JavaPlugin
  implements Listener
{
    public final Logger log = Logger.getLogger("Minecraft");
    public HashMap<String, Long> cooldowns = new HashMap();
    private int cooldownTime = 0;
 
  public void onEnable()
  {
    Bukkit.getPluginManager().registerEvents(this, this);
    getConfig().options().copyDefaults(true);
    saveConfig();
    this.log.info("Effects has been enabled");
    this.cooldownTime = getConfig().getInt("Cooldown");
  }
 
  public void onDisable()
  {
    this.log.info("Effects has been disabled");
  }
 
  @EventHandler
  public void onPlayerInteract(PlayerInteractEvent e)
  {
    Player player = null;
    if ((player instanceof Player))
        {
        Player p = e.getPlayer();
        if ((p.getItemInHand().getType() == Material.DIAMOND) &&
            (e.getAction() != Action.RIGHT_CLICK_AIR)){
            if (this.cooldowns.containsKey(player.getName())) {
                long secondsLeft = ((Long)this.cooldowns.get(player.getName())).longValue() / 1000L + this.cooldownTime - System.currentTimeMillis() / 1000L;
                if (secondsLeft > 0L) {
                    p.sendMessage(ChatColor.DARK_AQUA + "[" + ChatColor.GOLD + "QuickBoost" + ChatColor.DARK_AQUA + "]:" + ChatColor.GRAY + " You are in a cooldown for another " + secondsLeft + " seconds!");
                }
            }
            this.cooldowns.put(p.getName(), Long.valueOf(System.currentTimeMillis()));
              p.addPotionEffect(new PotionEffect(PotionEffectType.SPEED, 180, 2));
              p.addPotionEffect(new PotionEffect(PotionEffectType.JUMP, 180, 2));
              p.addPotionEffect(new PotionEffect(PotionEffectType.HUNGER, 100, 2));
              p.sendMessage(ChatColor.GOLD + "[" + ChatColor.DARK_AQUA + "QuickBoost" + ChatColor.GOLD + "]" + ChatColor.GRAY + ": Boost Activated!");
              p.getInventory().remove(arg0);
        } else {
            p.sendMessage(ChatColor.RED + "You don't have permission!");
        }
        }

 

p.getInventory().remove(new ItemStack(Material.DIAMOND, 1))

p.updateInventory()

The statement above is to be safe. I dont know if it works without it or now.

 

p.updateInventory() says: updateInventory() from the type Player is deprecated. should I add a supressor?

 

C0lA_K1nG
updateInventory() isn't necessary. Also, it's deprecated because "This method should not be relied upon as it is a temporary work-around for a larger, more complicated issue."