hashmap java | The Blog Pros

May 13, 2022

Java Hashtable, HashMap, ConcurrentHashMap: Performance Impact

There are a good number of articles that articulate functional differences between HashMap, Hashtable, and ConcurrentHashMap. This post compares the performance behavior of these data structures through practical examples. If you don’t have the patience to read the entire post, here is the bottom line: when you are confronted with the decision of whether to use HashMap, Hashtable, or ConcurrentHashMap, consider using ConcurrentHashMap since it’s thread-safe implementation without compromise in performance.

Performance Study

To study the performance characteristics, I have put together this sample program:

July 27, 2021

What Is HashMap? Introduction and Sample Programs | Java Collections Framework

In the video below, we take a closer look at HashMap and see an introduction and sample programs. Let's get started!

April 8, 2020November 6, 2020

How HashMap Works Internally in Java

In this article, we are going to see how HashMap internally works in JAVA. Also, we will have a look at what Java 8 made changes to the internal working of Hashmap to make it faster.

A HashMap is a map used to store mappings of key-value pairs. To learn more about the HashMap, visit this article: HashMap in Java.

November 1, 2019

HashMap: get() Vs. getOrDefault()

When a developer is working on a module, they always come across some form of data structure, like set, queue, list, etc. Data structures are used for storing Java objects in a certain fashion so that they are easy to retrieve when needed.

You may also like: How HashMap Works in Java

The right data structure makes functionality more efficient and effective — otherwise, it would be a nightmare as the implementation expands. You can start with a Map of one of the data structures where objects are stored in the key-value format. And with the help of key, we can easily retrieve the value in time complexity of O(1).