Two notes: 1) you may want to check against stack.length - 1 instead of 9. That will cause less bugs should you wish to change the size of the array. 2) printing an error and returning 0 may not be a good option for real-life projects. Instead, throw a RuntimeException.
Please use code tags when posting code; it makes it easier to read. I have edited your post; see how much better it looks. And please write your question in the text of the post, otherwise people won't realise what the question is!!
He's dead Jim. Grab his tricorder. I'll get his wallet and this tiny ad: