MODULE 2: ArrayList

Prelim Topic

ArrayList

• A class within the java.util package

• Provides dynamic-sized arrays in Java

• Part of Java’s Collections Framework

• It automatically adjusts its capacity as elements are added or removed.

Class Hierarchy and Interfaces

(Characteristics of ArrayList)

• ArrayList inherits from AbstractList class

• ArrayList implements the List interface

  • This means it adheres to the List contract, providing common list operations

Dynamic Sizing and Capacity Management

(Characteristics of ArrayList)

• ArrayList is initialized with a size (or default capacity)

• Its size can increase automatically as the collection grows

• It can shrink automatically if objects are removed

Random Access Capability

(Characteristics of ArrayList)

• Java ArrayList allows for random access to elements

• This means you can efficiently retrieve an element directly by its index ( e.g., get(index)).

Handling Primitive Types

(Characteristics of ArrayList)

• ArrayList cannot directly store primitive types (int, char, boolean, double, etc.)

• You must use wrapper classes (e.g, Integer for int, Character for char) when adding primitives to an ArrayList

  • Example: ArrayList<integer> numbers = new ArrayList<>();

C++ Vector Analogy

(Characteristics of ArrayList)

• ArrayList in Java can be seen as similar to a vector C++

• Both provide dynamic array functionality, allowing elements to be added or removed while managing underlying memory