List Interface

List is a child interface of Collection. It represents an ordered collection of objects. Key Features:

1. Insertion Order: Preserved (Elements appear in the order they are inserted).
2. Duplicates: Allowed.
3. Index-Based Access: Elements can be accessed via index positions (0 to n-1).
4. Null Values: Supported.

Implementation Classes

The List interface is implemented by:

1. ArrayList
2. LinkedList
3. Vector
4. Stack

1. ArrayList

• Underlying Data Structure: Dynamic Array (Resizable Algorithm). • Performance: Good for Retrieval (Random Access is fast). Slow for Manipulation (Insertion/Deletion requires shifting). • Synchronization: Not Synchronized (Not Thread-safe). • Growth: Increases size by 50% when full.

2. LinkedList

• Underlying Data Structure: Doubly Linked List. • Performance: Good for Manipulation (No shifting needed). Slow for Retrieval (Sequential Access). • Synchronization: Not Synchronized. • Interfaces: Implements both List and Deque.

3. Vector

• Legacy Class: Introduced in JDK 1.0. • Synchronization: Synchronized (Thread-safe). Slower than ArrayList. • Growth: Doubles size (100%) when full.

4. Stack

• Child class of Vector. • Principle: LIFO (Last In First Out). • Methods: push(), pop(), peek(), search().

ArrayList vs LinkedList