I think the title basically explains my issue. I have a water bucket as a part of a recipe, and I want to be able to return the empty bucket once the item is crafted.

 

Any ideas on how to do this?

You shouldn't have to do anything. I thought the whole container item business was already set up by vanilla code.

I am using a custom water bucket. Where in the vanilla code does it allow the normal bucket to be returned?

Its called a Container Item. In your item class you'll want to override the (two?) methods regarding container items and in one it'll be a boolean (return true) and other will be an item stack (return a new one of a bucket).

14 minutes ago, Draco18s said:

Its called a Container Item. In your item class you'll want to override the (two?) methods regarding container items and in one it'll be a boolean (return true) and other will be an item stack (return a new one of a bucket).

Since this is 1.14 you just do Item.Properties#setContainerItem

That's where it is. I didn't have my dev up and couldn't go looking for it easily. I just knew it was "around somewhere."