Why İt is not working?

[Rstarks07]

Why it is not working

cobblegen.txt

[null2264]

I assume that the file attached is just a portion of your config?
If not you should wrap it with another {}, like this:

{ // <-
	"customGen": {
		"cobbleGen": {
			"minecraft:end_stone": [
				{
					"id": "minecraft:end_stone",
					"weight": 100.0,
				}
			],
			"minecraft:granite": [
				{
					"id": "minecraft:granite",
					"weight": 100.0,
				}
			]
		}
	},
} // <-