EDUCBA

EDUCBA

MENUMENU
  • Blog
  • Free Courses
  • All Courses
  • All in One Bundle
  • Login
Home Software Development Software Development Tutorials Top Differences Tutorial Hash Table vs Hash Map

Hash Table vs Hash Map

Updated February 21, 2023

Hash Table vs Hash Map

Difference between Hash Table vs Hash Map

Hash Table vs Hash Map will give out the differences of Hash Table and Hash Map. Both of these are used to store unique keys using hashing techniques. These are based on hashing and map implementation data structure. Hash Table implements associative array abstract type, a data structure that maps keys to values. It uses a hash function in computing an index, known as hash code, into an array of slots or buckets from where the desired value can be found. Let’s dig deeper into the Comparison of Hash Table vs Hash Map.

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

Head to Head Comparison between Hash Table vs Hash Map (Infographics)

Below are the top 13 differences between Hash Table vs Hash Map:

Hash-Table-vs-Hash-Map-info

Key Differences between Hash Table vs Hash Map

Following are the key differences given below:

  • Hash Table was introduced in Java’s first version, i.e. JDK 1.0, but it was refactored in JDK 1.2 for implementing the Map interface, making it a member of the Java Collections Framework.
  • Hash Map was introduced in version 2 of Java JDK 1.2
  • Hash Table is synchronized and hence has slower operations compared to Hash Map. If a user is not working in a multi-threaded environment, Java JDK recommends using Hash Map.
  • Hash Table extends dictionary, i.e., it maps non-null keys to values. Users can look up the value that corresponds to keys.
  • In Java, Hash Table and Hash Map use java util properties like java.util.Hashtable and java.util.HashMap respectively
  • Hash Table and Hash Map don’t mention any insertion order in Java.
  • Both Hash Map and Hash Table are implementations of java.util.Map interfaces in Java
  • For Hash Map and Hash Table, Complexity offered by GET and PUT methods in worst and best case in O(n) and O(1), respectively.
  • Synchronization operation will result in poor performance and hence avoided, and Hash Map is the one which is used.
  • Methods like get(), put(), remove(), containsKey() provide constant time performance. Internally, these work based on the concept of hashing buckets for storing data
  • Hash Map and Hash Table are resized when a number of elements reach the loadFactor. These are faster with smaller loadFactor and take up space. Hashing function works better with prime number capacity.

Comparison Table

Comparison between Hash Table vs Hash Map is given below:

Hash Table

Hash Map

Hash table is the legacy class and was introduced before Hash map On the other hand, Hash Map is the advanced version of Hash Table and was introduced as a new class in JDK1.2
Hash Table is internally implemented in such a manner that no null key or null value is allowed Whereas Hash Map allows one null key and multiple null values
Hash Table is synchronized and thread-safe, hence can be shared with other threads There is no synchronization implemented in Hash Map, also not thread-safe. So it can not be shared among other threads without perfect synchronization code
Hash Table provides Iterator as well as Enumerator to traverse values stored in it Hash Map provides an iterator for iteration/Traverse the values stored in it
In Hash Table, due to synchronization, hash table slows down compared to Hash map but also eliminates extra coding As synchronization is absent, hash map is comparatively faster than hash table, preferable when there is no synchronization
Hash Table inherits dictionary class Hash map inherits Abstract Map class
Hash Table does not maintain mappings in any particular order Hash Map maintains insertion order and sorts mappings based on ascending key order
Hash Table is not a part of the collection framework. It was made part of collection framework member after implementing the Map interface Hash Map implements a map interface and is part of a collection framework since the start
If there is a thread-safe operation to be used, Hash table can be used as all methods in it are synchronized Hash Map is used for multi-threaded environment, recommended to use Concurrent Hash Map
Hash Table uses keys to implement hash code Hash Map is an advanced improvement on Hash Table.
Hash Table Efficiency is O(1) Hash Map Efficiency is O(1)
Enumerator in Hash Table is not a fail fast and throws ConcurrentModificationException Iterator in Hash Map is fail fast iterator
Hash Table is preferred over Hash Map for multi-threaded applications. Oracle has

provided with ConcurrentHashMap as a replacement for Hash Table

Hash Map is preferred over Hash Table for nonthreaded applications

 Recommended Articles

This is a guide to Hash Table vs Hash Map. Here we also discuss the hash table vs hash map key differences with infographics and a comparison table. You may also have a look at the following articles to learn more –

  1. RethinkDB vs MongoDB
  2. RabbitMQ vs Redis
  3. Informatica vs Datastage
  4. Eclipse vs IntelliJ
All in One Excel VBA Bundle
500+ Hours of HD Videos
15 Learning Paths
120+ Courses
Verifiable Certificate of Completion
Lifetime Access
Financial Analyst Masters Training Program
2000+ Hours of HD Videos
43 Learning Paths
550+ Courses
Verifiable Certificate of Completion
Lifetime Access
All in One Data Science Bundle
2000+ Hour of HD Videos
80 Learning Paths
400+ Courses
Verifiable Certificate of Completion
Lifetime Access
All in One Software Development Bundle
5000+ Hours of HD Videos
149 Learning Paths
1050+ Courses
Verifiable Certificate of Completion
Lifetime Access
Primary Sidebar
All in One Software Development Bundle5000+ Hours of HD Videos | 149 Learning Paths | 1050+ Courses | Verifiable Certificate of Completion | Lifetime Access
Financial Analyst Masters Training Program2000+ Hours of HD Videos | 43 Learning Paths | 550+ Courses | Verifiable Certificate of Completion | Lifetime Access
Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Live Classes
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Java Tutorials
  • Python Tutorials
  • All Tutorials
Certification Courses
  • All Courses
  • Software Development Course - All in One Bundle
  • Become a Python Developer
  • Java Course
  • Become a Selenium Automation Tester
  • Become an IoT Developer
  • ASP.NET Course
  • VB.NET Course
  • PHP Course

ISO 10004:2018 & ISO 9001:2015 Certified

© 2023 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

Let’s Get Started

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you

EDUCBA
Free Software Development Course

Web development, programming languages, Software testing & others

By continuing above step, you agree to our Terms of Use and Privacy Policy.
*Please provide your correct email id. Login details for this Free course will be emailed to you

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA Login

Forgot Password?

By signing up, you agree to our Terms of Use and Privacy Policy.

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

Loading . . .
Quiz
Question:

Answer:

Quiz Result
Total QuestionsCorrect AnswersWrong AnswersPercentage

Explore 1000+ varieties of Mock tests View more