Hello, I want my plugin to generate a world (1000 x 1000), surrounded by bedrock and spawn in the middle. How can I achieve this?
Well, if you know how to create large rectangles of material using for loops, you can simply use default world gen and then put bedrock walls 500 blocks in each direction from spawn. If you want a custom worldgen within the walls, you may have to find a tutorial on how to modify worldgen to adequately understand it.