Solved Why is this giving me a NullPointerExeception?

So I have this code, before it was giving me NullPointerExceptions. I added a null check and a check to see if the item had ItemMeta before comparing the ItemMeta. Now, it is giving me an error where I checked if the item has ItemMeta? Help?

Code:

Code:

    public void onInteract(PlayerInteractEvent event)
    {
        Player player = event.getPlayer();
        Action action = event.getAction();
        if(player.getItemInHand() != null)
        {
            if(player.getItemInHand().hasItemMeta())
            {
                if(player.getItemInHand().getItemMeta().getDisplayName().equals(ChatColor.GOLD + "XP " + ChatColor.AQUA + "Jar"))
                {
                    if(action.equals(Action.LEFT_CLICK_AIR) || action.equals(Action.LEFT_CLICK_BLOCK))
                    {
                        if(!(Integer.parseInt(player.getItemInHand().getItemMeta().getLore().get(0)) <= 0))
                        {

It's giving me an error on this:

Code:

if(player.getItemInHand().hasItemMeta())

 

Whats the error?

 

You're actually not checking if the item in hand has meta.
You're just checking if there's even an item in hand.
Try adding getItemMeta() for the first if statement.
If that throws a NullPointerException (which could only be
the case with nothing in hand [be sure to test that!]), add it
after the first if statement.

And your issue should be solved!

 

Not all items have a display name! Or lore!

 

InteritumStudios But I thought that hasItemMeta() returned true or false and if it was false then there is no ItemMeta. Hmmm so I should do this instead:

Code:

if(player.getItemInHand().getItemMeta() != null)

Or is it because some items have item meta, but not lore, so I should do the code above followed by this:

Code:

if(player.getItemInHand().getItemMeta().getLore() != null)

Right?

Jamesthatguy Sorry for double-posting but I will post the stack trace when I get back on my computer

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

If the player has no item in the hand, the itemstack from getItemInHand() is null. Add a null check:

Code:

if(player.getItemInHand() != null && player.getItemInHand().hasItemMeta())

 

That's exactly what he's doing...

 

Rocoty Thanks for letting him know, that was right in my original code

 

Zach_1919 Could you provide the stacktrace please?

 

Rocoty Here's my updated code:

Code:

package me.Zach_1919.xpjar;
 
import java.util.ArrayList;
import java.util.List;
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.Sound;
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.player.PlayerBucketFillEvent;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.ShapedRecipe;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.plugin.java.JavaPlugin;
 
public class Main extends JavaPlugin implements Listener
{
    ShapedRecipe xpjar = new ShapedRecipe(setStartingData(new ItemStack(Material.GLASS_BOTTLE), ChatColor.GOLD + "XP " + ChatColor.AQUA + "Jar")).shape(" ! ","@#@"," $ ").setIngredient('!', Material.DIAMOND).setIngredient('@', Material.GOLD_INGOT).setIngredient('#', Material.BLAZE_POWDER).setIngredient('$', Material.GLASS_BOTTLE);
 
    public void onEnable()
    {
        getServer().getPluginManager().registerEvents(this, this);
        Bukkit.addRecipe(xpjar);
    }
    public void onDisable()
    {
        Bukkit.clearRecipes();
    }
    @EventHandler
    public void onInteract(PlayerInteractEvent event)
    {
        Player player = event.getPlayer();
        Action action = event.getAction();
        if(player.getItemInHand() != null)
        {
            ERROR: if(!(player.getItemInHand().getItemMeta().getLore().isEmpty()))
            {
                if(player.getItemInHand().getItemMeta().getDisplayName().equals(ChatColor.GOLD + "XP " + ChatColor.AQUA + "Jar"))
                {
                    if(action.equals(Action.LEFT_CLICK_AIR) || action.equals(Action.LEFT_CLICK_BLOCK))
                    {
                        if(!(Integer.parseInt(player.getItemInHand().getItemMeta().getLore().get(0)) <= 0))
                        {
                            player.playSound(player.getLocation(), Sound.ORB_PICKUP, 1, 1);
                            player.setLevel(player.getLevel()+1);
                            player.getItemInHand().setItemMeta(subLore(player.getItemInHand().getItemMeta()));
                        }
                        else
                        {
                            player.sendMessage(ChatColor.DARK_PURPLE + "[" + ChatColor.GOLD + "XP" + ChatColor.AQUA + "Jar" + ChatColor.DARK_PURPLE + "]" + ChatColor.RED + "This bottle does not have enough XP!");
                        }
                    }
                    if(action.equals(Action.RIGHT_CLICK_AIR) || action.equals(Action.RIGHT_CLICK_BLOCK))
                    {
                        if(!(player.getLevel() <= 0))
                        {
                            player.playSound(player.getLocation(), Sound.ORB_PICKUP, 1, 1);
                            player.setLevel(player.getLevel()-1);
                            player.getItemInHand().setItemMeta(addLore(player.getItemInHand().getItemMeta()));
                        }
                        else
                        {
                            player.sendMessage(ChatColor.DARK_PURPLE + "[" + ChatColor.GOLD + "XP" + ChatColor.AQUA + "Jar" + ChatColor.DARK_PURPLE + "]" + ChatColor.RED + "You do not have enough XP!");
                        }
                    }
                }
            }
        }
    }
    public void onBucketFill(PlayerBucketFillEvent event)
    {
        ItemStack item = event.getItemStack();
        if(item.equals(setStartingData(new ItemStack(Material.GLASS_BOTTLE), ChatColor.GOLD + "XP " + ChatColor.AQUA + "Jar")))
        {
            event.setCancelled(true);
        }
    }
    public ItemStack setStartingData(ItemStack item, String name)
    {
        ItemMeta meta = item.getItemMeta();
        List<String> lore = new ArrayList<String>();
        lore.add("0");
        meta.setDisplayName(name);
        meta.setLore(lore);
        item.setItemMeta(meta);
        return item;
    }
    public ItemMeta addLore(ItemMeta meta)
    {
        List<String> lore = meta.getLore();
        String product = String.valueOf(Integer.parseInt(lore.get(0)) + 1);
        lore.set(0, product);
        meta.setLore(lore);
        return meta;
    }
    public ItemMeta subLore(ItemMeta meta)
    {
        List<String> lore = meta.getLore();
        String product = String.valueOf(Integer.parseInt(lore.get(0)) - 1);
        lore.set(0, product);
        meta.setLore(lore);
        return meta;
    }
}

I decided to change the getItemMeta() != null to !getLore().isEmpty() because I thought it might be giving me an error because of there being no lore, but it's still giving me an error on that line. Here's the error:

 

what about checking hasLore()?

 

I hate NullPointerException's they take FOREVER to find out the stupid problem and it is always simple!!!

 

Rocoty That exists? That might help...

EDIT: nope

 

inventorman101 They do not take long to fix. An average NPE only takes me about ten seconds to fix.

Zach_1919
ItemMeta could be null and the item's lore could be null.

Code:

private final xpJarName = ChatColor.GOLD + "XP " + ChatColor.AQUA + "Jar";
public boolean isXPJar(ItemStack i)
{
     if(i == null)return false; //Ignore if no item is in the hand
     if(!i.hasItemMeta())return false; //Ignore if the item has no metadata
     ItemMeta im = i.getItemMeta();
     if(im.hasLore())return false; //Ignore if the item has lore
     if(!im.hasDisplayName())return false; //Ignore if the item has no display name
     return xpJarName.equals(im.getDisplayName());
}

 

Technius Well I just tried it on my server and it worked! Thanks!

 

Technius sometimes that is the case but not always. You can't assume until you have seen the problem.