I have not found where you can NORMALLY learn to code at the level of minecraft mods (not to mention the server cores). I would be very grateful if you give me a link.
I know people like me have already zadolbali, but is it possible to make the kernel support Spigot? After all, in the server folder all exactly is minecraft_server_1.12.2.jar why not do the same only with spigot-1.12.2.jar? Or suffer and do as in KCauldron one fine file. And don't write me about the sponge!!!! IT'S NOT CONVENIENT AND IT DOES NOT HAVE THE NORMAL PLUGINS.