Java 8 CompletableFuture Tutorial Part-2 | thenApply(), thenAccept() & ThenRun() | JavaTechie

In this tutorial we will understand how You can attach a callback to the CompletableFuture using thenApply(), thenAccept() and thenRun() methods
#javatechie #Java8 #CompletableFuture @Multithreading
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[@rohitchobharkar747]

Waiting for next session @Java Techie

[@TheEntium]

Truly amazing.. the way you explain is like a flow of river.. with to the point example .. this is really what I love your examples..... really appreciated your hard work brother that you put on every videos .. please continue this Completablefuture series to the end.. Once again thank you brother.. keep growing

[@malayasinha414]

Implemented CompletableFuture in one of my spring boot service just by seeing only your video and now it is working absolutely perfect. Thanks a tonne.

[@pinpaigurung3654]

Waiting for third session Sir. Thank you

[@kavyasudhakar]

Please make part-3 of this series.

[@sandeep_begudem]

Thank you Basanth for the wonderful presentation, it would be really great if you do a part -3 and demo the process for combining multiple CompletableFuture threads.

[@shanashafkat]

Never thought coding can be so peaceful. You are beyond anything and above everything Thank you for this amazing piece

[@jvivekanand7875]

Great explination sir, waiting for your third session. Thank you very much.

[@venuparva]

Very nice video...Please share Part-3 link with .thencompose() n other functionalities...Really appreciate your effort towards it...Thanks a lot for your service :)

[@mahimakaushal7381]

Awesome learning always from Java Techie

[@MuraliM.A.]

Nice video, please create part 3 on this

[@gauravvijan03]

Eagerly waiting for your next tutorial for the same series

[@rakibulhasan1923]

you are always excellent as a teacher ,as a human being...salute

[@foddiebyage9696]

Pls continue such important topics in Java including testing and database queries

[@subhrajeetpadhy]

Awesome explanation and I can see your hard work. Please release the third session for combining thread results.

[@vinodnayak27]

I really enjoyed part1 and 2 great content 😍. can you please make part 3 as well.

[@LokeshMawale87]

Nice video and very well explained Basant. Can you please add exception handling part for the same. It will be very useful

[@Javatechie]

Sure Lokesh

[@ainigma100]

Thank you for the amazing video! Can you please upload Part 3 as well

[@shanashafkat]

Hey @javatechie, I could not thank you enough for these videos. Please release PART 3 video.

[@Javatechie]

I will do part 3 since i found very less response in this content so i stopped it in middle

[@shivangiubarhande3276]

@@Javatechie Please prepare part 3 waiting for it. You are excellent at this !!

[@Javatechie]

Noted and will try to close in next weekend for sure

[@kumaresanperumal2581]

Thanks.

[@ILuvBilli]

Very nice and clear explanation, waiting for 3rd part

[@cooldude20able]

Amazing explanation and hard work, please release the further videos soon 😄

[@abhaymishra8112]

Thanks to explain very clearly. Please create a video on thenCombine() & thenCompose()

[@satyabatigoswami1735]

waiting for third part 😇Great content !

[@jianwenliu458]

This is awesome, thank you, looking for the release of the further videos

[@akhilthammishetty3097]

Here independent code from all the apply methods is executing first i.e print statements ,we can see SOP statements are being printed first, so this way multithreading is being achieved.

[@7thwik]

yes, each of them are executing in a separate, but it doesn't have much of use, because each thenApply() method is dependent on the output of the previous thenApply().

[@user-ez4fz2oq1c]

Pls make 3 part it's very useful

[@harshverm776]

Yes, Please

[@deepaksetia461]

very nice explanation brother, waiting for next part.

[@ThePomelo09]

your tutorials are awesome, excellent teacher

[@NaveenSaisri]

Your content and explanation is awesome, please do the Part-3 of completableFuture

[@SANDIPKUMAR-es7qh]

Thanks for crearing such a informative video, waiting for part3

[@Javatechie]

Okay i will do that

[@SANDIPKUMAR-es7qh]

​@@Javatechiethank you😊

[@pradeepjain1889]

Grt , impressive . Create NEXT video

[@swapnilmedhe6679]

Simply awesome @ Java Techie appriciate your efforts

[@maheswarbehera1]

Nice explanation on CompletableFuture. Please proceed with some other methods if possible.

[@SyedIbrahimMohamedIsmail]

Thank you so much. please help us with more real time examples for any of your forth coming videos.

[@salehhassan6057]

I have read books and seen many videos about this topic. Nothing of them has helped as much as yours done. You are amazing. Thanks a lot Waiting for part 3...

[@Javatechie]

Thanks will add part 3 . Since I uploaded 2 video but didn't get positive response so stopped it . But anyway I will complete 3rd one .

[@salehhassan6057]

@@Javatechie Thanks a lot 😇❤

[@salmanbaig3582]

@@Javatechie Please Sir upload Part 3 also. These videos are gems. Amazing thank you so much

[@Javatechie]

Okay will do that

[@salmanbaig3582]

@@Javatechie 🙏🙏thank you

[@SandeepAS-ov3fk]

simply amazing...

[@myakhandbharat-2024]

awesome Job !! Waiting for your third part , if you already have it then please share the link

[@ManishKumar-qx1kh]

sir can you please create a playlist of DSA and Spring Beginner to Expert it will help a lot of people. Really appreciate the way you explain.

[@rahimkhan-fh9dd]

Great video basant

[@narraleelakrishnavasavi9757]

This is so helpful, could you please cover remaining concepts also

[@sivagdvs6884]

Hi bro. Please continue the series

[@Javatechie]

Will do that

[@sanathrayala2745]

waiting for the next session Basanth please complete the series

[@pratishrutipanda6461]

Nice content 👍

[@dhruvwadhwa9259]

Waiting for next session

[@firewater1045]

Very nice

[@PradeepKumar-db7pe]

Thanks @JavaTechie! One Question- Using customThreadPool; should be slow in performance considering there will be multiple context switching among threads. Whereas in case of fork join pool, all the task being executed by single thread only i.e no context switching. I think It doesn’t make sense having multi-threads when tasks are interdependent like in this case. But yes making use of thenXxx is awesome. Thanks for your explanation!

[@manojtailor2683]

Even we are using multiple threads to complete the whole task, arent they executing in sequence because next thread depends on the output of first thread?

[@AbhaySingh-ds9et]

Hi @JavaTechie Please make video on ThenCompose and thencombine and exception handling as well and also cover all.topics will be very helpful for all subscribers. Always you create some awesome content..kind of your job only thanks.

[@Javatechie]

Sure abhay will do that

[@AbhaySingh-ds9et]

@@Javatechie Hoping will receive it soon. Thanks

[@AmritAgarwal07]

Super content

[@vaibhavlodha5398]

Thank you for the video this is a great explanation. Question: Seems like all these tasks will only run serially since next thread depends on the completion of the previous thread. Trying to understand how would the usage of thenApplyAsync be helpful here ?

[@ikramfaruqui4093]

very helpful

[@random-characters4162]

thank you very much sir!

[@harshverm776]

Thanks

[@sujitkumar2196]

Good Explanation bro...so when we can expect next tutorial.

[@jagabandhujena9476]

Hi sir..,waiting for part 3 video, plz upload 3rd part, many thanks...

[@Javatechie]

Okay buddy I will do that

[@sivadara5677]

@JavaTechie, Hi Sir Can you please do video on allOf, thenCompose etc call back functions so that it would be very helpful for us sir ..

[@Javatechie]

Okay i will

[@sivadara5677]

@@Javatechie thank you sir .. I am watching and practicing all your videos both Java, angular and devops to become FSE Sir.. My sincere thanks to you sir for all you are doing for us..I have cleared 3 interviews by watching your classes only..You are my God sir..🙏🙏🙏

[@AnuragTripathiShiva]

Hi Basant, First of all thanks for your extremely and informative videos on every concept of java & microservices. I am bit curios in case of suppyAsynch(), when we have provided executor with 5 threads. But It seems like when we use thenApply(), each subsequent task is dependent on previous one. So, how this can be achieved or run by multiple threads. Correct me if I am wrong.

[@pnworks9186]

Thank you Sir. this is very helpfull

[@varunvijaywargi5497]

Hi, this is simply an amazing tutorial. However, I have a question that I'm confused about. If we have provided our own executor with 5 threads, then since each of the "thenApplyAsynch" is based on the outcome of a previous one (I.e first get pending training employees, get their email and then send email), will it not be a problem? Or how does it improve performance here? Also, another question is how does concurrent executiion and multi threading work on a container based environment?

[@dmitrikonnov922]

Great question. I wonder likewise.

[@7thwik]

Yes, even I have the same question. If each of thenApply() is dependent on the output of the previous thenApply() method, then what is the use here. Even though it executes in a separate thread, it still needs to wait for the other thread to complete its execution. This is a bad example to demonstrate multithreading I feel.

[@swagatrath2256]

Good explanation of the concept. My doubt - are we really achieving any parallelism here though? since each part of the task is being executed only when the previous one is done and each one of them runs on a single thread. So is it not same as writing the complete logic line by line in a main() and let it execute sequentially?

[@tejamanu6690]

Basant, one small request could you please start a series on Kafka event driven architecture(EDA).

[@Javatechie]

Okay I will

[@spaul1408]

I really enjoyed Part 1 and Part 2..Amazing content.. Can you please make part 3?

[@Javatechie]

Okay sure i will do that

[@sumitarora2554]

@@Javatechieyes please share part 3 video also

[@mohammedshabbir1347]

Great video basant. Can you also please create videos on other topics of completable future. I can only see 2 videos on completable furure in your java8 play list.

[@murugansivaraj7340]

Just a doubt here, what is the point in having thenApplyAsync() here, because anyway every task has to wait for the previous task to be completed. So It really doesn't matter if we run it in one thread or multiple threads. Multi threading comes to play when one task does not really depend on the other.

[@Javatechie]

No purpose of this method to expect return type from other thread then process it . To verify you can pass your custom ExecutorService

[@zurumogbonda3225]

Good lecture as always.. please is the 3rd one out?

[@AshishYadav-se4db]

Amazing content Sir, I was waiting for this, thanks alot sir 🙏❤️

[@vishnudasmankar8387]

Waiting for your third session sir

[@priyabratprasadmohapatra363]

Please if you can make a video on the complete evolution of Java multithreading till Java 8 or above.

[@Javatechie]

Will do

[@prashhanthnelakanti4992]

This video was very helpful and could be better if there is time complexity also involved

[@Javatechie]

You are talking about code time complexity

[@prashhanthnelakanti4992]

@@Javatechie I mean the time taken by the thread to finish the task ...something like that

[@rakeshjalui9063]

Could you please share part-3 video link, which will cover other topics thenCompose, allOf(), anyOf() you mentioned at the end of part-2 video?

[@karthickkumar4150]

Hi Sir, Thanks for explaining the details clearly. Can you tell me how to handle exception while doing this asynchronous calls.

[@Javatechie]

Yes i will cover that

[@nareshrudroju4943]

Please release 3rd session

[@AbhaySingh-ds9et]

@JavaTechie Have one question here in this example is the call is asynchronous and one thread is not waiting for other thread to complete its task. Because all steps defines seem to be depend. Can you provide some explanation will be great.

[@Javatechie]

Okay 👍

[@AbhaySingh-ds9et]

Can you please answer this questions.

[@nikhileshyoutube4924]

Bro create a video on java learning path brother for beginners it will be worth from developers like you

[@shubhamjumde9076]

Hi, this video is very helpful ! Can we have any video series for Consul and Vault with Microservices and Spring Boot . Also , can we cover inter services communication in Microservices architecture with ActiveMQ? Please consider.

[@Javatechie]

Hi Subham , please check out my both spring boot and microservices playlist, all above mentioned concepts already covered

[@shubhamjumde9076]

@@Javatechie Thank you ! 😀

[@kelvintsangxxx7581]

thx

[@abhis1560]

Waiting for third session. Please start one soon.

[@Javatechie]

Will upload buddy

[@narayanreddy7449]

Amazing content, can you please do one tutorial on groupby and partitionby using streams

[@Javatechie]

Okay I will definitely try this

[@harishhari1310]

Thanks for the tutorial. in my use case i want 3 methods to be executed concurrently & the output needs to be binded together. could you please suggest

[@arunbhandari5132]

What is the benefit of using multiple threads if they are happening in synchronize manner?

[@Javatechie]

It's not processed in synchronously please check I shown the results with sopln statement

[@Sharma.Shivam]

good explanation I have one question Executors.newCachedThreadPool() versus Executors.newFixedThreadPool() can you elaborate please

[@zamirdr]

Thankyou for a very clear tutorial, can you tell me how can I use exceptionally key word between tasks you showed here so if one service/task fails like fetching from DB then we can execute fallback method?

[@ajisegirisunday2885]

Nice work.. Can we use completetablefuture with stream parallels? Like parallelstream().map(). Thanks

[@Javatechie]

Didn't get you

[@ajisegirisunday2885]

@@Javatechie I mean after getting the data from db when applying the then Applyasync method can we use parallel streams instead of the ordinary stream before mapping the data

[@swatimalik9752]

I have one doubt, as supplyAsync() used when we have to return something, why the return type here is CompletableFuture ? This was suitable for runAsync ().

[@Javatechie]

You can change your return type as per your requirement please checkout my first video . Here I just want to show demo of future chaing so didn't specify return type

[@flowchart5471]

Waiting for third part Basant.

[@learnamazingtech3694]

Even though it’s executed by different threads it’s executing sequentially

[@Javatechie]

No add a print statement and also keep your executor

[@dipakramole]

Waiting for part 3

[@18ajai]

Whats the use of thenApplyAsync in this example. Even if each step is running in a different thread but each thread is still waiting for the output of previous step to execute. So will it make a difference in perfoemance?

[@Javatechie]

Very poor response guys. Based on your demand I am preparing content but really disappointed with you guys feedback. Anyway keep learning and share

[@santhoshshetty4500]

Its a great series Basant, please continue

[@abdus_samad890]

Liked your video friend... Very nice...

[@darkknightgotham2172]

please complete the series

[@Hariprasadization]

Waiting for part3

[@kavyasudhakar]

Waiting for part-3

[@Maddy4645]

Could you please make video regarding intellj Ide It could be helpful for us Basant

[@oldaccount137]

Here one future is depending on other because without returning how other task will do it's processing , then what is the use of Asynchronous programming . Can u please explain it more clearly because supplyAsync when return the value then only we can proceed furthur so it is dependent on some other task . Also explain all other methods of completable future

[@Javatechie]

Yes correct buddy but Here the context is to chain multiple future together . There is no way in java to unblock completely while working on multi threading

[@krishnendughosh1212]

Hi Basant, Thanks for this excellent video . Had 1 question , How can we create an asynchronous thread for each iteration in a loop and join those at the end ?

[@akashkharade2259]

Thanks for such a beautiful explanation. Is part 3 released? If yes please give link for that

[@Javatechie]

No it's not released

[@LeoLeo-nx5gi]

@@Javatechie I hope you check this comment, we are eagerly waiting for the next series on this, thanks a ton ^_^

[@Javatechie]

Buddy I check and will try to publish asap

[@LeoLeo-nx5gi]

@@Javatechie thanks for your reply and support!!

[@abhishekwasave9010]

How can we securely shutdown executor when using supplasync with thenrun ?

[@GVB438]

Can we use this to return jpa data or export data into file is there any best example

[@Javatechie]

Offcourse why not

[@buenasdias786]

Please add further videos sir

[@chilukabharath4809]

nice video, but in this use case we can fetch direct emails from db by writing all those conditions in a single shot, with out writing multiple tasks. can you give me any other use case, or ignore if my question is wrong..

[@Javatechie]

Yes buddy I could fetch all emails directly using query but in video to explained future chaing I took this example

[@jedans3437]

Third session?

[@Chaloobolo]

Hey do you have any paid course for Java , Spring Boot and Microservices . I need to buy.