... In a way that seems completely unnecessary. My plugin (creaturebox) uses a creature spawner's durability (ItemStack.getDurability()) to keep track of the spawner's type while it is in a player's inventory. Up until build 602 or thereabouts, this worked quite well. Now, when I query the item in hand for it's durability, it always returns zero for creature spawners, regardless of the item's actual durability. Further, when I query the item for it's material data, it returns null (which explains the durability issue). This seems to me like a completely unnecessary restriction in the way that bukkit works - the minecraft server has no difficulty keeping track of metadata for items that don't actually use it, so why does bukkit need to restrict our usage of otherwise unused metadata? Btw, without a reversal of this change, I'll probably abandon creaturebox, as I don't see another way to keep track of this bit of metadata.