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 d7c5065457d910f3e5481fda046d368d5f66f67b..58045d500a6fbb7eb568f48c7d8ce7730d357577 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) {