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 6ca9a5cf426befde4882d78df5fd8202b73ddbeb..504a56fb2f2901c67ed22b9f0a57eb8db10ca4df 100644
--- a/src/main/java/net/minecraft/world/item/ItemStack.java
+++ b/src/main/java/net/minecraft/world/item/ItemStack.java
@@ -249,7 +249,7 @@ public final class ItemStack {
     }
 
     public boolean isEmpty() {
-        return this == ItemStack.EMPTY ? true : (this.getItem() != null && !this.is(Items.AIR) ? this.count <= 0 : true);
+        return this == ItemStack.EMPTY || this.item == null || this.item == Items.AIR || this.count <= 0; // Paper
     }
 
     public boolean isItemEnabled(FeatureFlagSet enabledFeatures) {