Implementing a stack as an array

[fam2315]

If I was going to write my own stack class, but use an array to do so, wouldn't I have to initialize the array to some size in order to do so? But since a stack is virtually unbounded in size, implementing it using an array seems like a bad choice, would you agree?

[Norm]

Underneath a lot of collection classes there are arrays. What that means is you have to be able to resize the array ie create a larger one and copy old one,
or have some logic that will span/jump from one array to another depending on the index value. For example the first array would be for indexes 0-99, the next for indexes 100 to 599 etc. Your logic would convert an index of 102 to 2 and use the second array.

[Dark]

I'm not 100% sure what you're trying to accomplish, but is there a reason why you can't use an ArrayList? Since the size isn't set in stone you would be able to make your needed array as big as you need.