My modpack doesn't have any problems, but in my modpack.zip, I got a map file which is not in the soloplayer when I launch the modpack.
I recently download a modpack (of someone) and in Soloplayer, there was a custom map. I want the same.
OR, do you know how could I, in java, add an event on a button (GUI button) to open a specific map ? I coded the GUI and I don't know the term of opening a specific world.