Java Programming

I'm trying to get some homework done for a Java course that I'm doing right now. This is not a question asking for people to give me code, for I will not learn that way. Instead I would like to know what you guys think I should use to store all the labels, textboxes in (array vs arrayList)

http://www-acad.sheridanc.on.ca/~jollymor/prog24178/images/lab2Shot1.jpg

Just so you know, the guidelines want me to use a gridlayout, lable, textboxes and such. HOWEVER, the problem I'm having is figuring out why the hell the teacher put this sentence as a guidline,

"Your program should make use of arrays (which might include ArrayList objects). You will be graded on the efficiency of your program (i.e. where you would choose an array over an ArrayList).

So why on earth would anyone use an arraylist on this? Won't an array suffice? Considering the labels, gridlayout, buttons don't have to be resizable?

Message was edited by:
ManRed