ItemStack var = null; -> ItemStack var = ItemStack.EMPTY;and
ItemStack inventory -> NonNullList<ItemStack> inventory;Afterwords, I was able to right click and bring up a GUI. After some changing of integer values, I was able to the size the GUI to the correct size and bring the slots to their correct places on the GUI. But now an issue I'm present with is removing an item from the two item slots when the cursor is not holding a stack of items.
I also still need to add crafting to the mint. I added a check in the Update() method for the block's TileEntity file so if an iron ingot or gold ingot is in the input slot, it sets 4 coins of iron or gold in the output slot.
GitHub of the Mod
Hopefully, I can get finish Mint block once and for all by tonight.