List Interface

A List is an ordered collection (also known as a sequence). The user of this interface has precise control over where in the list each element is inserted.

ArrayList

The ArrayList class is a resizable array.

• Fast: Random access (getting element by index).
• Slow: Modifying (inserting/deleting) in the middle (requires shifting).

import java.util.ArrayList;

ArrayList<String> cars = new ArrayList<String>();
cars.add("Volvo");
cars.add("BMW");
System.out.println(cars.get(0)); // "Volvo"

LinkedList

The LinkedList class is a doubly-linked list.

• Fast: Inserting/deleting elements.
• Slow: Random access (must traverse the list).

Interactive Code

Play with ArrayList!

Quiz

Next Steps

What if we don't want duplicates? Sets are the answer.