Holes can be caused by overmixing, or unevenly or insufficiently folding in the flour. The mixture should be soft and dropping at this stage, and if it is too dry, pockets of air can get trapped. This also happens if the flour and raising agent are not sifted together thoroughly.
To prevent cracking, make sure you use the right sized tin and that the oven is not too hot. Place cakes in the center of the oven, not too high up where it will be hotter and the cake will peak and crack.
** Asian Recipes