Edit: The problem was some functions in the Block class weren't overriden
I'm making my custom furnace (microwave) and when I open it, the inventory slots and hotbar slots appear but my furnace slots do not. It gives an index out of bounds exception with a limit of 36 but I haven't set that limit anywhere in my code. There are no hints to where it is in the error except it's to do with container (which is quite obvious). Any ideas. Here is my github repository: https://github.com/HarryTechRevs/MinecraftModding/tree/HarryTechRevs-FurnaceDevelopment