What Is Data Structure in Java With Example?


Heather Bennett

What Is Data Structure in Java With Example?

Data structure is a way of organizing and storing data in a computer so that it can be accessed and manipulated efficiently. It provides a systematic way to manage data and perform various operations on it. Java, being one of the most popular programming languages, offers several built-in data structures that can be used to handle complex data efficiently.

The Importance of Data Structures

Data structures play a crucial role in programming as they help optimize the performance of algorithms. By choosing the right data structure, you can significantly improve the efficiency of your code and reduce the time complexity of operations.

Java provides a wide range of data structures such as arrays, lists, queues, stacks, trees, graphs, and maps. Each data structure has its own advantages and is suitable for specific scenarios.


An array is a collection of elements stored in contiguous memory locations. It allows you to store multiple values of the same type under a single variable name. Arrays have a fixed size once declared and can be accessed using an index.


// Declare an array of integers
int[] numbers = new int[5];

// Assign values to the array
numbers[0] = 1;
numbers[1] = 2;
numbers[2] = 3;
numbers[3] = 4;
numbers[4] = 5;

// Accessing array elements
int thirdNumber = numbers[2];
System.out.println("Third number: " + thirdNumber);


A list is an ordered collection that allows duplicate values. Java provides two main implementations of lists: ArrayList and LinkedList.

// Create an ArrayList of strings
List<String> names = new ArrayList<>();

// Add elements to the list

// Accessing list elements
String firstPerson = names.get(0);
System.println("First person: " + firstPerson);

// Iterating over the list
for (String name : names) {

Queues and Stacks

A queue is a collection that follows the FIFO (First-In-First-Out) principle. Elements are added to the end of the queue and removed from the front. On the other hand, a stack follows the LIFO (Last-In-First-Out) principle, where elements are added and removed from the top.

Java provides Queue and Stack interfaces, which can be implemented using classes such as LinkedList or ArrayDeque.

// Create a queue using LinkedList
Queue<String> queue = new LinkedList<>();

// Add elements to the queue

// Remove and retrieve element from the front of the queue
String firstFruit = queue.poll();
System.println("First fruit: " + firstFruit);

// Create a stack using ArrayDeque
Stack<Integer> stack = new ArrayDeque<>();

// Push elements onto the stack

// Pop and retrieve element from the top of the stack
int topElement = stack.pop();
System.println("Top element: " + topElement);

Trees and Graphs

Trees and graphs are non-linear data structures that represent hierarchical relationships. In a tree, each node has a parent-child relationship, while in a graph, nodes can have multiple connections.

Java provides various implementations for trees and graphs, including TreeSet, TreeMap, HashSet, HashMap, etc.


Data structures are an essential part of programming in Java. They allow you to efficiently organize and manipulate data based on specific requirements. By understanding different data structures and their use cases, you can optimize the performance of your code and write more efficient algorithms.

Remember to choose the appropriate data structure based on the problem you are trying to solve. Experiment with different data structures to gain a deeper understanding of their strengths and weaknesses.

Discord Server - Web Server - Private Server - DNS Server - Object-Oriented Programming - Scripting - Data Types - Data Structures

Privacy Policy