1. List Interface
ArrayList class implements the List Interface
import java.util.List;
Lists are generic (java 5.0)—Elements are declared to be of a specific object type when a list or collection variable is declared.
<E>is a the object type—tells compiler to check for that element type when a collection is used
List<E> list = new ArrayList<E>();
List<String> list = new ArrayList<String>();
Margaret Winans, 2014 AP TIP

2. List<Integer> list = new ArrayList<Integer>();
The variable list is declared to be of type List<Integer> (the interface) but is instantiated as type ArrayList<Integer> (the implementation)—preferred byAPCS
This has the advantage of making the code applicable to any List. For example, a single change:
List<Integer> list = new LinkedList<Integer>();
The AP Quick Reference Guide (given to you for the AP exam) only gives methods of the List interface
Margaret Winans, 2014 AP TIP

3. The ArrayList Class
Contains a sequence of elements ordered by position
Unlike an array in that:
It uses methods rather than [] to manipulate elements.
It tracks both logical and physical size.
The logical size is 0 when created & automatically adjusts as needed.
The positions available for access range from 0 to the logical size minus 1.
ArrayList can be printed without a loop
Margaret Winans, 2014 AP TIP

4. AP Quick Reference Guide: List Interface
The List interface methods below are all inherited by the ArrayList
This is the actual screen shot from the QRG
Margaret Winans, 2014 AP TIP

5. The ArrayList Class
E = obj type
not length
boolean add(obj) Appends obj to end of the list; returns true
Margaret Winans, 2014 AP TIP

6. Adding/Changing values using an ArrayList
//create a list of Integer objects
List<Integer> list = new ArrayList<Integer>();
//add int values to the list
for (int i = 1; i <= 100; i++)
list.add(i);
// Increment each int in the list
for (int i = 0; i < 100; i++)
list.set(i, list.get(i) + 1);
Margaret Winans, 2014 AP TIP