From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 21 Dec 2016 03:48:29 -0500
Subject: [PATCH] Optimize ItemStack.isEmpty()

Remove hashMap lookup every check, simplify code to remove ternary

diff --git a/src/main/java/net/minecraft/world/item/ItemStack.java b/src/main/java/net/minecraft/world/item/ItemStack.java
index 201ba7250b298f4a91bc45f5954f54ae557305f2..cac92ccacc9d5ff17c70ee266cf12bacce6242ea 100644
--- a/src/main/java/net/minecraft/world/item/ItemStack.java
+++ b/src/main/java/net/minecraft/world/item/ItemStack.java
@@ -208,7 +208,7 @@ public final class ItemStack {
     }
 
     public boolean isEmpty() {
-        return this == ItemStack.b ? true : (this.getItem() != null && this.getItem() != Items.AIR ? this.count <= 0 : true);
+        return this == ItemStack.NULL_ITEM || this.item == null || this.item == Items.AIR || this.count <= 0; // Paper
     }
 
     public ItemStack cloneAndSubtract(int i) {