createTemporaryWorldWithGenerator
public static World createTemporaryWorldWithGenerator(String worldName, World.Environment environment, ChunkGenerator generator)
Creates a fresh temporary world using a caller-supplied ChunkGenerator, with no template folder on disk. Unlike createVoidTemporaryWorld, this does NOT auto-append an identifier — the caller is responsible for choosing a unique final world name. If a world with worldName is already loaded, it is returned immediately (matching loadVoidTemporaryWorld).
Post-create settings mirror createVoidTemporaryWorld: spawn not kept in memory, difficulty HARD, autosave off (these worlds are ephemeral).
Return
the created World, or null on failure
Parameters
worldName
unique world folder name under getWorldContainer
environment
nether / end / normal
generator
the ChunkGenerator responsible for producing surface blocks