Ronald,
A Queue is a FIFO (First In, First Out) data type that can be visualized as a line, like at the checkout counter. (In fact, the
word queue is another word for a line used in this context, though the word is not as common in popular US English.) Here is an illustration :
Hopefully this clearly explains how a queue behaves... as far as actual implementation you can use anything : an array, a vector, a tree, a hash table, etc. to actually implement. I would look into the
Collections API. Since a queue is a type of Collection it would fit into this interface, and it will also give you an idea of the sorts of data types you can use to implement a queue.
HTH,
-Nate