Crafting table Duplication glitch

I was playing around in minecraft, and found this duplication glitch that only works in singleplayer, to replicate this glitch, you have to make your game glitch like crazy(by either lowering your max frame rate, expanding entity distance, expanding chunks, etc...), and then put a desired item into a crafting table, keeping the crafting table gui open, you then end the task for java se enviroment, open up your world after you re open minecraft, and your items are duplicated