_SithLordBacon

*facepalm* I forgot to change the Map to be Map<ItemStack, ItemStack> . Nevermind, I have changed that now! Thanks for your advice.

Is this more efficient? It might not be what you were telling me, but this seems to work too.

Thank you so much! It worked after I did a quick Google search. The whole problem was mainly the way that I couldn't work out how to iterate over a set properly, so I ignored it. This is how I did it after.

When I learnt Java I didn't read anything about "enhanced for" loops. I will research about them and then tell you the results!

I am having some trouble iterating over every furnace recipe and assigning a recipe to each recipe. It is meant to assign the output of the recipe as the output of the smelting recipe one of the inputs as the item being smelted. Here is the code I have. The print line is for debugging and only prints "null". Any suggestions are welcome.