size() on any Collection returns the
number of elements it contains
Collection can be iterated, as it implements
the Iterable interface
Collection<Integer> grades = new ArrayList<Integer>();
// some grades get added...
Iterator<Integer> iter = grades.iterator();
while (iter.hasNext()) {
System.out.println(iter.next());
}
Collection<Integer> grades = new ArrayList<Integer>();
// some grades get added...
for (Integer i: grades) {
System.out.println(i);
}