So this?
public ItemEntity(World worldIn, double x, double y, double z, ItemStack stack) {
this(worldIn, x, y, z);
this.setItem(stack);
this.lifespan = (stack.getItem() == null ? 6000 : stack.getEntityLifespan(worldIn));
}
Lets look at that constructor for a moment.
It has the following parameters:
World worldin
double x
double y
double z
ItemStack stack
Are any of these the type EntityType?