How to replicate:
1) Create new world;
2) Type -> Buffet;
3) Area -> Surface;
4) Biome -> Basalt Deltas;
Then game just freeze while trying to create world with these settings.
Also there is no any normal way to close Minecraft, so only way is kill process "javaw.exe".
P.S.: With area = cave or floating islands world generating without any problem.