The Collections Framework - Beginning Java - page 644

Retrieving Objects
As you saw in the simple example earlier, if you have the index for an element in a vector, you can obtain
the element at that position by using the get() method. For the names vector you could write the following:
String name = names.get(4);
This statement retrieves the fifth element in the names vector. The return type for the get() method is
determined by the type argument you used to create the Vector<> object.
The get() method throws an ArrayIndexOutOfBoundsException if the argument is an illegal index
value. The index must be non-negative and less than the size of the vector.
You can retrieve the first element in a vector using the firstElement() method. For example:
String name = names.firstElement();
You can retrieve the last element in a vector by using the lastElement() method in a similar manner.
Neither method is implemented in the ArrayList<> class. However, both a vector and an array list have the
flavor of a list about them, and if you want to process the objects like a list, you can obtain an iterator.
Accessing Elements in a Vector through a List Iterator
You've already seen how you can obtain all the elements in a vector using an Iterator<> object, so I won't
repeat it. You can also obtain a ListIterator reference by calling the listIterator() method:
ListIterator<String> listIter = names.listIterator();
Now you can go backward or forward though the objects in names using the ListIterator methods that
you saw earlier.
It is also possible to obtain a ListIterator<> object that encapsulates just a part of a vector, using a
listIterator() overload that accepts an argument specifying the index position in the vector of the first
element in the iterator:
ListIterator<String> listIter = names.listIterator(2);
This statement results in a list iterator that encapsulates the elements from names from index position 2
to the end. If the argument is negative or greater than the size of names, an IndexOutOfBoundsException
is thrown. Take care not to confuse the interface name ListIterator , with a capital L, with the method of
the same name, with a small l .
Additionally, you can retrieve an internal subset of the objects as a collection of type List<> using the
subList() method:
List<String> list = names.subList(2, 5); // Extract elements 2 to 4 as a sublist
The first argument is the index position of the first element from the vector to be included in the list, and
the second index is the element at the upper limit — not included in the list. Thus this statement extracts
elements 2 to 4, inclusive. Both arguments must be positive. The first argument must be less than the size of
the vector and the second argument must not be greater than the size; otherwise, an IndexOutOfBoundsEx-