14.11 HashMap and HashTable in Java

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HashMap and HashTable both implements Map interface.
HashTable is synchronized and HashMap is not synchronized.
HashMap is faster than HashTable.
HashMap, LinkedHashMap, TreeHashMap, HashTable implements Map Interface
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[@spacetime_wanderer]

Great going sir! I tend to first search your channel for things I am looking for before looking elsewhere. Keep up the great work, sir.

[@Avaylia]

Incredibly helpful video! Super clear and concise :)

[@alextrex3975]

very helpful, thank you for the effort you've put into these videos

[@shriramjadhav7891]

Thank you so much for such partical and to the point explanation. Thank you so much over again.

[@tmzpanda]

3:05 HashMap, LinkedHashMap, TreeHashMap, HashTable implements Map Interface 4:55 "keySet" method 5:31 "Map.Entry(I) and "entrySet" method 7:59 LinkedHashMap, TreeHashMap vs HashMap

[@TechProgrammingIdeas]

Hai Visit my hash map video

[@Affliction604]

That's one of the best tutorials i've ever watched

[@AbdulRizwan]

the way you teach is really awesome :) very nice work.

[@ger1991mess]

You make it look so simple!!! Thank you very much sir.

[@Ketrixx]

Great job as always !!!!

[@setudutta3905]

You da best... very well explained.

[@taruntosh7970]

This is the best tutorial in entire internet. Thanks for the effort.

[@TechProgrammingIdeas]

Hello Visit my hash map video

[@gener6995]

Hi navin, good job....keep up the great work...can you please make a video on internal working of map in Java.

[@rukikar5643]

Very good explanation. Thank you

[@maverickmegastar]

🙏 After scanning through a ton of implementations this has to be one of the most concise video on this topic.

[@shabirafshar9773]

You made me understand man thank you SIR

[@iskandarzakirov230]

Very clear explanation, sir! Great Job! Like + Subscription.

[@ashwiniv7053]

Awesome videos, learning Java thru ur videos is a breeze. Small clarification - HashTable is synchronized and shouldn't it be a single thread instead of multiple threads.

[@user-sy1xb4uq3q]

very helpful,Amazing explain. thank you

[@muruganpalani2007]

T hanks boss for the simple clarifications ............

[@rovsenhuseynov8368]

Amazingly informative video.

[@mahmudhr2760]

Excellent example to make it explained.

[@archerli7257]

Thank you! Very helpful tutorial

[@user-lb1fl7sh8m]

you are the best man god bless you

[@vengateshan7800]

The way of explanation is very crystal clear and understandable

[@sreekanthreddy9087]

nice explanation.Thanks for information......

[@mugdhashrivastava]

amazing explanation. thank you so much sir

[@asifkarimbherani6386]

Hey when are you planning to upload the next video to this playlist? So far it was very good and helpful and we are waiting for more videos on collection playlist.

[@shubhamjadhav4728]

7 years ago u were learning collections just wanna ask how's ur programming going..?

[@RahulPahuja1991]

Thank you so much for this Navin

[@Aeizium]

Awesome video :)

[@naturefriends3531]

Great explanation, very useful

[@soybenh9340]

Thank you for the tutorial, am using jdk 8, it doesn't support these data structures :hashtable,hashmap...what should i do?

[@soumitramehrotra5547]

sir,is there any way to input the entries at once into a hashmap rather than using put() function for very entry ?Also is there any way to see a particular value, and not all the value in the map.

[@algorithmsguide5076]

Thank you Sirji !!

[@poojajoshi3174]

finally my map concept clear thankyou sir :)

[@hermesmercuriustrismegistu4841]

Thx for the valuable information

[@saddamahmad2310]

thank you very much sir for this video

[@mathsforiit-jee9730]

it was direct in the point .. learned quickly thnx.

[@nithyasivaprakasam4925]

Very clear explanation.. superb.. thank u so much sir.. ur videos are easy to understand even if it is a big thing..

[@ravindraprajapati468]

this video give very good information about haaaaaaashmap

[@user-xd1pv6ze6x]

Lot's of thanks dear sir, Awesome videos, learning Java videos is a amazing. Perfect clarification - HashTable is synchronized and shouldn't it be a single thread instead of multiple threads.👍👍👍👍👍👍

[@technical9871]

Nice video . Thanks for very useful information

[@kanchapaudukumbura7991]

Do you have video about hashtable implementations/functions? (like your videos of linkedlists,ques,stacks) I

[@FindARandom]

Love telusko since 2019

[@srikanthjk9]

Thanks for information. What if we have more than two columns in excel, how to store such values?

[@faixan13]

We can iterate directly also on entry set rather than saving first in Set. for(Map.Entry i : map.entrySet()) { System.out.println(i.getKey()+" " + i.getValue()); }

[@surykaushal2140]

yes you can, he was just making it simpler to every one like if you have map.entrySet() then it can be assign to Set. Also we all can save variable , it was done here for readability

[@angelguzman477]

Navin, you look so much better now, your English has improved and you explain better, Its amazing seeing how much you have improved

[@Sumedh_v1]

It's a 5 years old video, he's now the knowledge source for crores of developers. Please mind before commenting.

[@amolgenius06]

in Map.entry , entry is inner class of interface map

[@shaiknagoorvali8983]

Great tutorial sir

[@madanreddy2322]

One thing is wrong here,in hash map multiple threads will work at a time where as in hash table only single thread at a time( you did a mistake in comparison table )

[@saipoojitha7553]

Sir,the video really very helpful...I have a doubt...is it possible to map HashMap....

[@MsWonderlands]

so...for storing key-value pairs, we could very well use Arrays, by storing keys as indices and values as the Array Values. What is so specific about HashMaps?

[@nayanrajvansh6705]

At 4:04 What would be the output if we execute System.out.println(phonebook.values()).. Will it be sorted if yes then on what basis .. Please explain .Thanks in Advance

[@Karbonblade]

"If you know the key, you will get the number". Well I got arrested instead.

[@GaneshKumar-vh4it]

😂

[@simm5622]

Thank you 👍

[@parshuramrathod1681]

Because of you I got placed in compan.thankyou so much

[@shashgo]

if the keyset is one way of getting all the key value pairs then is there any reason to use the other way of map.entry? If the end result is to get all the key value pairs without individually knowing each key, then what is the need of the map.entry method, and why would they want to ask about that in an interview.

[@RahulKumar-de2rw]

I've seen many tutorial of a Java but this is the best one, sir why don't u start pega software tool?? It is also based on Java,

[@MrRannis]

Nice, how to get the length of value of a perticuler key?

[@channelkerr]

Is it possible to have a multiple attributes instead of just 1 key to 1 value like a CSV? eg Name, age, weight Bill, 18, 60

[@rajarshibasu007]

Hello sir what is the meaning of this line please help (although it is not related to this video) : HashSet hs=new HashMap();

[@seenu007]

I like your channels name...innovative!

[@aishwaryarokade1150]

Nice video ..could you please give an example of hashmap under hashmap

[@rezaurrahman6455]

super video. thank you :)

[@anikevin]

Thank you sir

[@nameizdanny]

hi sir i am big fan of you,sir can you make a video on what is difference between Hashcode and equals method in collection

[@nagavadlapudi]

How to print whole key set? - 4:54 What is entry set and how to print it? - 5:31

[@addicted09111]

can we give more than one value to a single key ? any method to do that ?

[@Arrezzz]

thank you.

[@sriramakrishna7188]

hello sir, I have a small doubt which is asked by my friend.how can we create an object of HashSet with the help of object of ArrayList. please give me the correct solution.

[@satyavarmalutukurthi]

thank u so much

[@kalppatil7568]

thank u telusko sir --regards from an alien

[@anupkmr03]

Whatever you have explained that is perfectly fine but I have another doubt which is related to memory leak. When we don't implement the equals and hashcode then it takes from object class in that case too it gives us some unique code, So how GC is unable to clean up those unused objects when "get" method called internally then it definitely returns its hashcode and that is a expected case. But this whole scenario is a memory leak problem so please explain this.

[@BuffaloBlack]

Fantastic

[@praveenswarnakar5135]

in your phone book example if i want to have duplicate name then what should be the right way to implement key value pair?

[@samk8806]

Duplicate keys are not allowed

[@prameshkumar4932]

Naveen, How will we fetch all key and its values using old for loop ? i am trying but not able to do it with normal for loop ? could u please help..

[@mackensonreginaldmichel399]

Hello. Thanks for the awesome tutos. Is there a difference between: Entry and Map.Entry?

[@TechProgrammingIdeas]

Hai Visit my hash map video

[@satyavarmalutukurthi]

today I learned a new concept

[@RahulKumar-de2rw]

Good one sir

[@thetuchofheart2928]

you have some tutorials regarding concurrent collections

[@ShoeibShargo]

Can anyone tell me, what is this sign ? Is it a paramerter or what?

[@girjashankar7925]

can you please tell me,why in hashtable ,no null key is allowed?

[@hamdamboyurunov6034]

good thanks sir

[@maweryoutube9852]

YOU ARE AMAZING AS ALWAYS ^_^

[@saivarun1833]

what is the use of e.setvalue("III")

[@mamatanaik9699]

what is difference between map.keySet() and map.entrySet(),at what condition to use these things

[@saurabhchopade3891]

I have one problem how to add 2 friend have same name but in Java we cannot use one key two time then how to implement the phone book in Java we use two value at a time but not key

[@DhrumilShahDOTin]

ConcurrentHashmap ?

[@mohamedawnallah2957]

Wonderful

[@WisomofHal]

You are the G.O.A.T

[@ShaeekhShuvro]

Hello sir do you have video on arraylist?

[@nancyreva5722]

Is HashMap working single thread? HashMap is unsynchronized right!.. so it's used multithreaded only, but you mention hashmap works with a single thread in the hashmap and hashtable difference.. if it is right you mentioned, please explain.

[@anbarasusubramaniyan693]

could you pls explain how to add list into hashmap !!!! and as well as how to add the hashmap inside the hashmap???

[@dhavalshah3519]

Its was tough to understand especially entry,but though thank u

[@lankeshraut9]

help me alot to clear concept thank you \

[@jkk23-g7c]

Can we not create an ArrayList of objects?

[@melinatomala7831]

Hi to all of you.. I have a question.. if I want to do a program to check and keep updating student data.. something like: 1 see data 2 find student data 3 exit for that... what do you think I have to use..hashtable or hashMap?

[@Sushantway]

If your application is multithreaded go for hashtable or use hashmap

[@AravintakshanarunagiriRA]

thank u da mota thala

[@priscilla00167]

Hi, Ive got this assement for the college: I have to implement a system for viewing and updating of student data. This data is giving by a .txt, for example: 201504123|Carla Arias|IN-TEL|20|10|2|6.8 201402947|Paul Zambrano|IN-TLM|21|18|0|8.1 201508364|||||| 201502342|Ivan Torres|IN-CC-ST|19|6|0|7.5 201201723||||||, my question is: Which method is better to implement this, hashmap or hashtable?

[@supratimmukherjee2427]

can you plz send me the link of the next practicle video

[@laxmichandra4904]

Tq sir..

[@Sunshine-oh8pl]

Nice....