false if the iteration is complete,
Usually iteration is considered to be complete if all elements of the
underlying data structure were handled through calls to
in custom iterators any logic may be used to determine the completion
Returns the current item of the
Iterator and advances to the next one.
This method is not required to check
hasNext() first. A call to this
false yields unspecified behavior.
On the other hand, iterators should not require a call to
before the first call to
next() if an element is available.