What is an ArrayList?

An ArrayList in Java is a resizable array implementation of the List interface. It allows dynamic memory allocation, where elements can be added or removed as needed.

Advantages of Using ArrayList

  • Dynamic Resizing: Unlike arrays, ArrayList can dynamically resize itself, providing flexibility.
  • Random Access: It allows fast retrieval of elements using indices.
  • Easy Element Insertion and Removal: Simplifies adding and removing elements compared to arrays.

Disadvantages of ArrayList

  • Performance Considerations: Slower than arrays for certain operations due to resizing overhead.
  • Memory Overhead: Consumes more memory due to dynamic array resizing and object storage.

How to Create an ArrayList in Java

Creating an ArrayList is straightforward. Here’s the basic syntax:

ArrayList<Type> list = new ArrayList<>();

Example of Creating an ArrayList

ArrayList<String> names = new ArrayList<>();

Adding Elements to an ArrayList

You can add elements using the add() method:


You can also add elements at specific positions:

names.add(1, "Charlie");

Accessing Elements in an ArrayList

Use the get() method to access elements:

String firstElement = names.get(0);

Iterating with a for loop:

for (String name : names) {