Discussion in 'Plugin Development' started by DJCowGaming, Oct 23, 2019.

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    I don't usually use the forums for help, but I really feel like I have been lately. I'm trying to have custom recipes where the items have to have custom names.
    I have a recipe here:
            ShapedRecipe recipe = new ShapedRecipe(new NamespacedKey(pl, "ARCANE_SWORD_1"), ArcaneSwords.sword1());
            recipe.shape(" i ", " i ", " b ");
            recipe.setIngredient('i', Material.PRISMARINE_SHARD);
            recipe.setIngredient('b', Material.BLAZE_ROD);
    which does exactly what it needs to. I want to use the PrepareItemCraftEvent to check if the items being used to craft have the names that I want them to.
    The event is here:
        public void onPrepareItemCraft(PrepareItemCraftEvent event) {
            CraftingInventory inv = event.getInventory();
            ItemStack[] items = inv.getMatrix();
            if (equal(inv.getResult(), ArcaneSwords.sword1())) {
                if (!(items[0] == null && items[1] != null && equal(items[1], ArcaneMaterials.shards(1)) && items[2] == null
                        && items[3] == null && items[4] != null && equal(items[4], ArcaneMaterials.shards(1))
                        && items[5] == null && items[6] == null && items[7] != null
                        && items[7].getType() == Material.BLAZE_ROD && items[8] == null)) {
        private boolean equal(ItemStack item1, ItemStack item2) {
            String name1 = item1.getItemMeta().getDisplayName();
            String name2 = item2.getItemMeta().getDisplayName();
            return name1.equals(name2);
    This also does what I want it to do, though when I craft the item, it throws a NPE at line 30, which is String name2. I don't know what is wrong with it, or why it would be throwing a null pointer exception. Do I need to add a check for both the ItemStacks in the equal method to see if they have ItemMeta? Any help is appreciated.
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    Does the error occur every time you use equal()? Or is it just one specific time?
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    The error only fires at equal(items[1], ArcaneMaterials.shards(1)), and the error points to line 19 (this line) and line 30, which is the String name2.
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    name2 must not have a display name, or the ItemStack, item2 is null.

    Also, what version are you using.
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    Though I know for a fact that the ItemStack has ItemMeta and a display name, since ArcaneMaterials.shards(1) has ItemMeta and a custom display name.

    I fixed what was throwing the npe. I added a null check for the result in the event and a null check for item1 and item2 in the equal method.

    EDIT by Moderator: merged posts, please use the edit button instead of double posting.
    Last edited by a moderator: Oct 24, 2019
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