#10 - How HashMap works internally || Popular java interview question on collection (HashMap)

In this video, I have explained How HashMap works internally, what is hashing and HashCode, what is indexing and how is it calculated from Hashcode?
This is a very popular java interview question on collection (HashMap).
References taken from:
Java 8 API Doc
Oracle Java 8 Source Code
Geeks of geeks
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[@soumyajit443]

I have read about this from multiple resources.But I had never seen it in real 'how exactly it works'.You have explained so beautifully.Its just amazing. I would say you are "THE DRONACHARYA" (who was was royal preceptor to the Kauravas and Pandavas.)
Thank you so much for making this awesome video.Its so clear and precise.Thanks

[@naveenautomationlabs]

Most welcome:) keep learning 👍😃

[@soumyajit443]

@@naveenautomationlabs I want to get strong in logic building.I appeared for an interview but did not get selected in first round.They asked to write a program which would take input an Integer array having only zeros and ones and output will be sorted Integer like 000011111.I could not answer it.
Actually Naveen,I need a proper plan and guidance to get strong in my programming skills.Please guide me if you provide any personal training I would like to enroll for it as its high time and I want a change in my career.

[@rachakatladheer9059]

@@soumyajit443 use Sort Class
int arr[] = {0,1,0,1,0,1,0,1,1,0,0,1};
Arrays.sort(arr);
System.out.println(Arrays.toString(arr));
o/p - [0,0,0,0,0,0,1,1,1,1,1,1]

[@anushavenkatesan685]

@@soumyajit443 check his website. He s taking live classes

[@abhiPn9160]

Thanks sir....i searched many time for working of hashmap. But Didn't satisfied with explanation all they have. But after ur video now I am cleared about hashmap. Your explanation in simple and better 🙏 thnks sir

[@rd3316]

🙌take a bow Naveen . I searched this on internet and no one has explained it in such an easy way like you .

[@Ranjan-Singh89]

Thanks, Naveen for creating this whole java collection video series. In this series, you have really explained each and every collection framework topic in an awesome way and In fact, I am following a couple of automation tutors on RUclips but no one has explained these topics in such an easy and understanding way. 😊👍👍

[@sureshgarine]

I appreciate your research on Hashmap implementation under the hood, I remembered my college day's Hashing concept implementation, now I see in reality in debug mode. Thanks, Naveen. this is called bridging the gap between institution and industry. :)

[@naveenautomationlabs]

Thanks for your valuable comment. Thanks for your motivation.

[@swapnakadam1822]

The best explanation on How hashmap works internally, I have seen so many videos but I get confused instead of understanding but this is PERFECT....Thank you...

[@gita3354]

Excellent explanation Naveen . I was so scared to learn the collections concept in java. But you have made it like a cupcake . Thanks much for your time and effort. I don't think even the paid courses will give this much explanation for each nuke and corners.

[@sharvilpatil8742]

This is the best explanation one can ever get on Hashing and Hashmap. Great explanation Naveen!

[@kumargaurav4362]

In Java 8, HashMap replaces linked list with a binary tree when the number of elements in a bucket reaches certain threshold. While converting the list to binary tree, hashcode is used as a branching variable. If there are two different hashcodes in the same bucket, one is considered bigger and goes to the right of the tree and other one to the left. But when both the hashcodes are equal, HashMap assumes that the keys are comparable, and compares the key to determine the direction so that some order can be maintained. It is a good practice to make the keys of HashMap comparable.
This JDK 8 change applies only to HashMap, LinkedHashMap and ConcurrentHashMap.

[@Fortheluvoffood]

really good explanation... learning from your channel is very much easier than reading stuff on internet and reading books... precise explanation with good examples clears the concept easily rather than getting confused in it... appreciate your efforts and your easiness towards teaching these concepts... you do it so confidently and so easily... thankyou so much...

[@viveksinghbais4133]

Thank you, sir, I can't even imagine how much hard work and research are required to create such knowledgeable content. thanks so much

[@rakeshdora6]

Really appreciate your work and awesome explanation i saw several videos for hashmap implementation and work flow. But this is the BEST.

[@muzammilkhan382]

Thankyou Naveen Sir for your explanation! After banging my head for hours, and reading articles, finally found your video and understood how it works.

[@aryacode1705]

Thank you so much, sir, I can't even imagine how much hard work and research are required to create such knowledgeable content. thanks so much

[@gurunadhmitikela2918]

Wow.. what a wonderful explanation Naveen. Kudos to you for teaching this complex concept in such a simplified way. Really appreciate the hard work you would have put in to break this one brick by brick. :)

[@ambicaponnaluri7743]

All my queries regarding Harshmap were cleared after watching this.Awesome work😊
Keep rocking..
Thankyou much Naveen

[@lockdowndiaries4090]

super. simple and clear explanation. i have searched many videos. nothing compared to urs. great and thank you so much for helping us out

[@poonamsharma7026]

Thanks a lot Naveen.
You are right, it really gets difficult to understand from documentation, we need practical implementation, and as always you made it easy :).

[@sachida23]

Explanation is precise and crisp and well documented thanks for this post.

[@suyogdtalathi924]

Thanks !! After searching more for hashmap internal structure this one is the best explanation

[@prabhakarreddy9180]

Entire RUclips ur explanation is just awesome

[@mahiradolan4160]

Very detailed and excellent explanation. Thank you, Naveen!

[@sakshiaggarwal6199]

Thanks a lot Naveen. This was much needed to understand the internal working. 😇 Especially the debugging how it is calculating the hashcode is ultimate.

[@jatinsharma3792]

You always saves me in difficult situation where understanding is not easy. :D Thanks!!

[@dhareppasasalatti7102]

The best out of the best Explanation I have even seen on this hashmap.. Thank you sir for the effort.. It's was 💯💯

[@ruch3719]

Very well and crisp with what is required and the clarity of topic stays longer in mind ..with so neat and clear explanation.Hope you keep posting more content on data structures and common topic which are required longer

[@sreedevimoningi9739]

Thank you so much Naveen for this video, very detailed and excellent explanation you have given. I did really felt amazing.

[@utpalkanti]

Excellent explanation. Many many thanks for this kind of video. Recollecting my old college day topics now...

[@sujith6323]

Explanation followed by the important notes was very helpful. Really appreciate this Quality content.

[@b3creativevlogs815]

Superb Explanation Naveen now I understood the HashMap how its working...Thank you so much...

[@hasmukhmaniya4214]

Thanks for the video Naveen and one of the best video to understand HashMap functions.

[@Lipunknb]

the best hashmap internal working video on youtube. OP🙌

[@ashuiet]

Earlier I have tried to understand the "Hashing Concept" from several sources but it seems very confusing but the way you have expalain now this concepts has cleared now. So, Here after I can explain the hashing concept to anyone.
Thanks !! Naveen

[@naveenautomationlabs]

Glad that you got the concept. :)

[@sandeepchoudhary3882]

Awesome...very detailed explanation. Thank you Naveen !

[@charismatic2]

Thank you so much Naveen for detailed and clear explanation.

[@sumitbabel5415]

Exceptionally well explained , I would really like to express my gratitude for such a marvelous and clear explanation. To be honest I am able to understand and register it very nicely. Many thanks and God bless dear.

[@vandanamishra6748]

Your each video is so well explained .. after going through your videos my base is getting cleared on many topics .. keep making good videos.. god bless you for ur hard work ..🙏🙏

[@vinodkumar-ss3mb]

What a wonderful explanation sir
You made this topic so easy
God bless you 🙏

[@funved3371]

You have explained this complex topic in a way which is very easy to understand.
Thank you very much sir.

[@maheshuma741]

Superb explanation. I have never seen such a clean explanation. Thank you bro. Do more videos on tricky concepts like this

[@usmanahmad5448]

This is by far the best explanation.

[@shilpashravge5393]

Excellent session as usual. Things look so easy after your explanation.
Thanks for the efforts and time 😇

[@farazahmad9009]

Glad I came across this video. What a wonderful explanation. Thanks a lot!!

[@vemurisirisha8543]

Superb explanation sir. Thank you so much for all ur efforts!

[@msanyasirao5411]

Thank you.. Explained in an understanding of this typical hash code topic..Really Good

[@Anuragidiot1]

Great Video finally it helped me understand how it works Thank You Naveen

[@anjalijha1598]

As always best and this specific is really awesome Video on Hashmap internal working .

[@gopalpandurangan9768]

Excellent demonstration on HashMap. Thanks

[@gauravjaykar8126]

Appreciate your Work ,You Covered every Possible concept

[@shankumondal2881]

Awesome !! It's a very detailed explanation and very interesting . 👍

[@busijagannathrao2915]

Awesome explanation, but if the hashing explanation is more, like how it's calculating in which node the value will be inserting, then it will be the best-ever i saw in youtube.

[@nithyar767]

You have done a wonderful job Naveen ! Thanks!

[@dhandapani.sudhakar]

Thanks, Naveen for the clear explanation.

[@Sogdo]

Thanks for the video Naveen, very few content creators covers this topic.

[@shrutijoshi6496]

@naveenautomationlabs loved the explanation . Its actually amazing how you take this valuable time in explaining and putting out the most relevant explanation. Actually a FAN of yours.

[@naveenautomationlabs]

Thanks Shruti. Glad that it was helpful 😀

[@shobhit9826]

Yes this is the most important interview question I have also faced the same multiple times

[@naveenautomationlabs]

yes it is. please prepare it.

[@user-jz2up8hp3e]

Thank you for making this video. Loved your explanation, such an amazing content.

[@MrYashMundey]

I will never forget this now. Thank you for making it so easy :)

[@naveenautomationlabs]

My pleasure 😊

[@syedjami4033]

Amazing. Just loved the explanation.

[@likithahs2469]

really good. Thank you for posting the video. Very well explained

[@sandeshkumar9156]

RUclips really has some great teachers. If I get teachers like Naveen I would love to study all day.

[@shubhambansal6903]

Chal jhoota 😂

[@sandeshkumar9156]

@@shubhambansal6903 😂😂😂Why bro

[@Coolharshit149]

What an amazing explanation. Thanks :)

[@SomeshwarPhulari]

Awesome! made me consontrate and understand perfectly. Thanks....

[@priyanshusinha7056]

Good Explanation ❤❤ Thank you NAVEEN Sir

[@PravasaBharathiyaTelugodu]

its very good and you have captured all the key points.
keep rocking .. Thanks

[@parameshwarpr1364]

Well explained sir, thank you so much.

[@acridpoet2766]

Great video, absolutely great!

[@himanshikushwah8341]

Best explaination i got so far👍

[@AbsolutelyAJYoutube]

thanks for creating this video , helped me a lot in understanding this concept.

[@sujitharavuri3572]

Really appreciate this quality content.Thanks a lot.

[@naveenkumarchowki6717]

Thanks for give the information, I have learned so much...now I can explain got the clarity about how hash map exactly work internally...

[@naveenautomationlabs]

Glad it was helpful!

[@tonystark4917]

Best Explanation For Hashmap , Thanks.

[@sathishrajasekar1155]

Thanks Naveen, Useful video.

[@itzrajani]

Thanks much Naveen for the very detailed explaination.After subscribing to your channel started learning Automation core concepts with confidence. I couldn't even think of my youtube search without this "Naveen automation labs" prefix for Java, python, selenium, design patterns POM, BDD, Github, Jenkin's, concepts, etc, and whatnot.

[@naveenautomationlabs]

Thanks for watching @Rajani :)

[@amrendrakumar4280]

theory with practical ,very well explained

[@sangamdavangave4039]

Thanks a lot. It is a perfect explanation.

[@badrinathdanave]

Thanks a lot naveen for this great content.

[@kotireddy5272]

Great bro that's amazing explanation and easy to understand

[@raghugunda2732]

Very good explanation. Thank you so much

[@titusjennipalli4106]

Great explanation, Thanks

[@nithyarajaram9464]

Very well explained. Thanks a lot

[@pratikjadhav7407]

Good way of teaching & explanation Sir.

[@GibyAlex0606]

Thanks Naveeen , this is Awesome explanation

[@shobhitagarwal9321]

Thanks Naveen, really nice presentation.. 👍

[@jugautomation3102]

Amazing Naveen sir... today I got to know what is hashing and hashmap. thank u so muchh sirr.

[@naveenautomationlabs]

Glad that you got the idea about it. Thanks for watching.

[@fathimasifasyedmusthafa9410]

Well Done ... worth watching .. !!

[@anupdeshmane8827]

Its awesome easy to understand

[@vijayaraghavanvashudevan1977]

Awesome ♥ same index positions for Naveen and Tom. Thank you bro :)

[@naveenautomationlabs]

Glad that you liked it. :)

[@shalinianumula2108]

thankyou for explaining so clearly..

[@girishgk4902]

Awesome explanation.

[@anurani7084]

Wonderful and clear explanation 👏👏

[@sumitchaturvedi5933]

Excellent Explanation, Thanks, Bro...

[@panneerselvam.k1613]

Really now only i can able to understand
Thanks Bro

[@shubhamthakur614]

very nice video sir thank you for clearing our doughs

[@magicallife9299]

Best explanation of hash map

[@SarangHoley]

Thanks for the video Naveen, very few content creators covers this topic, and like this till now not available on RUclips 😊👍👍

[@naveenautomationlabs]

Glad you liked it

[@arnavpatil583]

Already cover this topic before 2 years check the links
ruclips.net/video/CojCE-ojdGY/видео.html

[@ankitmahajan8295]

@@arnavpatil583 but naveen's explanation is at different level. he explained it really well.

[@jugautomation3102]

@@ankitmahajan8295 I agre.

[@SarangHoley]

@@ankitmahajan8295 Absolutely correct Ankit, I am completely agree with you.

[@varshahiremath1189]

Nicely Explained Naveen

[@deepakdange5530]

awsome......Naveen

[@nivedaravi2241]

wonderful explanation

[@hemanthhemasurya8735]

this was really nice bro..thanks