ItemStack.asBukkitStack(null) should return Air. Fixes BUKKIT-3170

src/main/java/org/bukkit/craftbukkit/entity/CraftItemFrame.java

@@ -1,10 +1,9 @@
 package org.bukkit.craftbukkit.entity;
 
 import net.minecraft.server.EntityItemFrame;
-import net.minecraft.server.ItemStack;
 
 import org.apache.commons.lang.Validate;
-import org.bukkit.Material;
+
 import org.bukkit.Rotation;
 import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.craftbukkit.inventory.CraftItemStack;
@@ -26,8 +25,7 @@ public class CraftItemFrame extends CraftHanging implements ItemFrame {
     }
 
     public org.bukkit.inventory.ItemStack getItem() {
-        ItemStack i = getHandle().i();
-        return i == null ? new org.bukkit.inventory.ItemStack(Material.AIR) : CraftItemStack.asBukkitStack(i);
+        return CraftItemStack.asBukkitStack(getHandle().i());
     }
 
     public Rotation getRotation() {

src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java

@@ -242,6 +242,9 @@ public class CraftItemStack extends ItemStack {
      * Copies the NMS stack to return as a strictly-Bukkit stack
      */
     public static ItemStack asBukkitStack(net.minecraft.server.ItemStack original) {
+        if (original == null) {
+            return new ItemStack(Material.AIR);
+        }
         ItemStack stack = new ItemStack(original.id, original.count, (short) original.getData());
         stack.addUnsafeEnchantments(getEnchantments(original));
         return stack;