Multi-Threading in Spring Boot using CompletableFuture | @Async | JavaTechie

This video will guide you How to perform Multi-Threading in Spring Boot Using CompletableFuture also you will learn about Thread-pool Execution
#javatechie #CompletableFuture #SpringBoot #MultiThreading
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[@SrinivasuAvasarala]

Your videos helped me to learn the concepts, hands on and crack the job interviews, got the job offers. Thank you so much Sir🙏.

[@Javatechie]

Congratulations buddy for your new job . Good to hear that 🥰

[@avijitsharma5050]

5:33 - configuration bean for executor/ThreadpoolTaskExecutor 10:24 - parseCSVFile() [which contains try with resource] 13:14 - @Async , CompletableFuture.completedFuture(users); 22:41 - three threads for fetching data from H2 console 24:04 - join the result of three tasks using CompletableFuture.allOf(), join() method

[@codingshiv1670]

Its really annoying why the Java Techie doesn't add timestamps

[@Javatechie]

Shiva my role is here to explain the concept .if you understand it correctly then it's good .

[@codingshiv1670]

@@Javatechie As a presenter imo u need to care about user experience. Timestamps really help in that area. Eventually its ur call. BTW nice content. Recently found this channel. It would be more helpful to browse through the content more fluidly via timestamps of contents. Thanks for reply

[@Javatechie]

@@codingshiv1670 I completely agree with you. Going forward I will take care this for longer video

[@gopisambasivarao5282]

Appreciate your efforts Basant. God Bless you..🙂

[@jayjoshi1366]

This is the best video and explanation I have found to implement MultiThreading using SpringBoot and REST APIs. I am learning Spring Boot and trying to implement Multi threading in it. Thanks for the video. Please make more video on it using a complex scenario and complex API end points, maybe with 10 threads or more. Thanks @javatechie :)

[@shreem6447]

Well done explaining rare and tough topics using easy hands-on

[@lidwinx]

Basant, thanks for the video, well done, you always rock..!! Keep posting !!!

[@frankdux21]

this guy is a genius

[@umareddy2902]

I have implemented successfully and understood the concept very well plz keep posting videos like this.. Thank a lot for the videos on latest technologies.

[@duzgunkenan]

I smile everytime you say "Isn't it?" :D

[@Javatechie]

Why don’t you like it 😂

[@duzgunkenan]

@@Javatechie No, on the contrary, I like it :)

[@maheswaran.s]

I'm impressed with the way you explain. It is very clear, thank you!!👍

[@Bahmed825]

Very good tutorial.

[@0DarkPrince0]

I don't know why you have less subscribers. You are awesome

[@Javatechie]

Thanks buddy 😊

[@SaurabhKumar-rr1vi]

wow , such a simple explanation . Thank you.

[@nelsonraulbrizuela79]

you are very good at explaining my friend, thank you very much for the video

[@sreenivasl221]

Thanks.. Teaching is very understandable...

[@nagarajumuddey465]

nice

[@UmeshKumar-pq3kc]

Thank you so much for a wonderful example, I am going to use this today itself in of the big project of leading bank in the world.

[@hakkisan2508]

Don't understand the dislikes. He gives us lot of infos for some people to much for others to obviously. But other than you he gives us a lot of good information. You give us just zero Input only useless data on youtube server 😝

[@krishnasuripaka2480]

Super tutorial..u r always super...

[@sureshsadanala4639]

Basant bro, very good one 👍

[@thebachelorpad1110]

Jabardast! I am your fan buddy! keep doing good stuff!

[@manichhina3984]

very good explained !!!

[@aviksutar6694]

lovely

[@sandeep_begudem]

@Javatechie Thank you so much for the tutorial. I enjoyed learning it. Could you do a tutorial on rest of the methods that are available in CompletableFuture?

[@sriaya1743]

Nice video sir, hopefully you will extend this further for exception handling in completable future, running each tasks separately / stop running the tasks intermittently etc. Thanks

[@Javatechie]

Hi Sri , yes will do that 👍

[@manasipalkar9794]

this is amazing

[@sathiskumarp]

Thank you so much. It's really awesome

[@bhaktilatadash7619]

Thank u Brother for ur efforts....

[@shamsherali7284]

Man U rock .thanks for this valuable lecture

[@yuvarajs3510]

In getUsers API, you are calling the same services three times by two different threads, but findAllUsers method in service class will return the same data for each call. How is it consolidating the final data from three calls by different threads?

[@avinashverma7141]

I think the wait() method can distinguish the thread call.

[@ashutoshgupta9056]

Yes u are right, all those threads are doing the same job.

[@AmritAgarwal07]

Most interviews asked questions on the Executor framework. of thread Can you make a video on that?

[@vinodnayak27]

Hi Basant, I recently started to fallow your channel and loveedd the way to deliver the content😍. Can you please make a playlist on multi-threading and thread pools mapping with real time senarios in your style😎.

[@Javatechie]

Thanks vinod ☺️. Noted your suggestion

[@vinodnayak27]

@@Javatechie thanks❤

[@mjagan619]

Thanks for the knowledge sharing. What type of thread pool you have created in the video?

[@Javatechie]

Custom thread pool

[@JERILNADAR]

In the getUsersbyThread how do we return the list of users as response once all the all threads have completed their work and we join them.

[@compartelo007]

Great example, thanks

[@compartelo007]

I understand little in English but you speak slowly and then for me it was much easier, thanks

[@jean-baptistedioli1692]

Thanks for the video. I'm beginner and it's a little bit difficult to understand everything correctly. Is it possible to make a video to explain the "philosophy" by a schema ? with code example ?

[@AnkitKumar-yw2ue]

Liked this video. You demonstrated the thread pool concept well. But I think this is not a proper example of CompletableFuture

[@Javatechie]

Yes this is how we should use completableFuture

[@souvikadhikary8990]

Good One! But now Spring has provided us Flux & Mono with Reactive Repository interfaces!!! Java's features are becoming obsolete !! :(

[@Javatechie]

Yes reactive programming is more popular now a days .I will start a brand new series with it .

[@Igor-uz3vn]

Thanks for great tutorial!

[@chinnarajr8689]

Very good video, Could you please post a new video for handle the exception in completable Future(For example- There are two futures future1 and future2, then future1 is executed successfully and future2 is throwing exception but I want the result from future1 and send back to client). This is one of the interview question which I faced recently? Thank you

[@abhishekdubey5336]

Very Nice and quick hands on explanation for Multi threading, it would be great if you can explain a bit on how and why we need to create Executors and how Completable Future helps, to make the theory clear

[@pradeepvirtuele7160]

Yes I agreed @Abhishek Dubey It would be great if this explain in debugging mode

[@sivakumarreddivari686]

thanks for the crystal clear explanation. How to make it conditional. like for example I want to modify first 10 records in csv file to new emails and other thread should not process those 10 records until the first one is done ?

[@amanueltesfu6071]

You are fabulous. Thanks my friend!

[@seatconnect224]

it also will be good if you do some video about concurrency in Java with describing deadlocks and so on

[@ssshanmugam4514]

Please make a video regarding implementing dynamic search query using spring data JPA and pdf and excel generation

[@sinurao1017]

Hi JT, Small suggestion add subtitles to your videos incase if we miss any terminology

[@MirekKrenc]

Great, thank you.

[@psudhakarreddy6548]

Thank you 🙏

[@SohailKhan-gu2du]

Hey man.... U r very knowledgeable.. Can u create some. Complex apps... Using spring boot.. Kafka.. Multi threading n all.... Like handling huge traffics of request... Apart from this simple crud apps

[@johncerpa3782]

Good video!

[@balaveeraraghavareddy9764]

Very nice tutorial could you please make a video on how to write pojo to CSV in spring boot without using open csv

[@pratyusharajanala3750]

Thanks for the detailed explanation. I have a doubt here .Is saveUsers method which calls praseCSV method uses multi threading? If Yes , how it splits to read the data if we have only one Input CSV.

[@josheluis6610]

Maravilloso :3 me salvaste like y subscribir Saludos de Ecuador

[@arpit-jain]

Really appreciate your work. I have a question here, what if we want consolidated response of all Async call done inside a for loop instead of returning just Responseentity at 17:30. How to do that? And do these threads created by Spring stop automatically?

[@basketballfan4eva]

What is the benefit of returning a CompletableFuture in the REST Controller endpoint? I understand it frees up a tomcat thread, but in that case, why not just increase the number of tomcat threads?

[@Javatechie]

Hi , I believe Rather than increase thread count we can resuse them

[@vickeychoudhary7399]

thanks basant kumar sir

[@studyaccount5578]

The GET call with single thread showed JSON User data, but after u converted it to Multithreading the same GET call did not return any results. I was interested to see how the results from each threads are stitched together and does the sequence of the data fetched changes

[@Javatechie]

You need to join or combine all threads to get results

[@yogeshchaudhari9971]

Nice video...one question...say i have 3 methods....method1 calling method2....method2 calling method3.....in method3 a rest api is called for some processing..... My question is do we need to annotate all three method1 method2 and method3 with @async annotation....i have this scenario in my project and trying to implement a solution for same.... If you can help please

[@Javatechie]

No adding @Async in method 1 is absolutely fine but make sure all 3 method return types should be either void or Completablefuture

[@yogeshchaudhari9971]

@@Javatechie ok thanks...i will try this.... thanks for all ur videos and knowledge sharing...i regularly watch ur videos and i appreciate ur efforts u put in knowledge sharing

[@nerdamongus7465]

@@yogeshchaudhari9971 Is it also fine if we use CompletableFuture.thenApplyAsync?

[@ritesisright]

Nice... But you should have sumnerized code towards end... You doing too many things here...

[@Iyauricastillo]

Thank you for your video. I have a question please: Is this an alternative to DeferredResult method or maybe this is a better approach to handle async requests?

[@Javatechie]

Am not aware about this DeferredResult method

[@code_for_life-c1h]

hi java techie

[@sureshmanne7245]

I have seen your spring batch video also and so my confusion now where both of these videos (Spring Batch & CompletableFuture) are processing csv file to store and retrieve data. Which one is better approach to process the csv files and why?

[@Javatechie]

One is the framework that automates the process that is a spring framework and ComplerableFuture is just a way to perform concurrent flow

[@artem1554]

Thanks for a nice video! I've question regarding async method. Why in video for async method used CompletableFuture.completedFuture(users) and not CompletableFuture.supplyAsync(() -> users)?

[@muchukundareddy5315]

Thank you so much. But I did not see any difference b/w implementing using the traditional approach and using a thread pool.

[@Javatechie]

Last get method was actual implementation of multi threading

[@mohammedsalman6318]

You have great knowledge but work on your communication skills, voice and accent neutralization. These things matter when you are presenting to an audience. Work on it, surely you will get more subscribers. For instance, there is a channel named Codevolution that guy is having superb communication skills. The way he presents is beautiful and easy to understand as well.

[@Javatechie]

Thanks buddy definitely i will try to improve my skills

[@mohammedsalman6318]

@@Javatechie Yeah, everything is fine but I feel like you should write a script before creating a video. That way, you can get more attention from a viewer. Take sufficient pauses in between the video, invest in your mic and voice etc. Apart from that you have superb knowledge and so thankful of you for bringing good content and giving your precious time to learners and the community. It really gives us the confidence on such crucial topics 🙏.

[@Javatechie]

Thank you buddy for your suggestion.definitely I will keep improving quality of my video going forward and I agree I should go with script

[@aayushkc2306]

how can i make a real time push notification in java web app ?? can you make the video series on long-polling and short polling features?

[@aman_bharti]

Can you please explain the advantage of using ThreadPoolTaskExecutor over SimpleAsyncTaskExecutor?

[@krishnendughosh2368]

You get more control while using ThreadPoolExecutor.......like setting up core pool, max pool (understand these two) You get the queue feature. In the simple one it creates one thread for each task, no concept of queue. Threadpool is also resource friendly since it uses pool and dont just create a new thread for each new task. Also there is a bound mechanism which prevents it from creating infinite no of threads. You can set up the thread names too in threadpool...and manage the thread lie cycles in a much better way. You can use the Simple one if you are working on a personal or small project but in a company or for any big project you should use ThreadPoolExecutor

[@frankdux21]

Danke!

[@Javatechie]

Thank you for your support buddy. Keep learning 😊

[@UmeshKumar-pq3kc]

Whoever disliked- Either you are not having knowledge of springboot or you don't like knowledgable videos

[@adobongasin214]

But how can you use the Threads? in your example you have user1,user2,user3 and join them all but how can you return them as response with the results from the DB?

[@АлексГладун-э5с]

If something will go wrong in the saveUsers method the response in any case will be Created, right? Because as I see, since service.saveUsers is invoked in separate threadPool spring is returning the response without waiting the end of execution

[@Javatechie]

Yes exactly , even though there is any exception in any thread it won't stop your execution . But there is better solution to handle fault , will do that

[@srogirala]

Very good content. But please improve your accent.

[@mayanksen3061]

Thankyou sir...

[@AbhimanyuKumar-xe5dq]

Hi basant we can use supplyAsync() also so why we need @Async annotation any benefit.

[@krupagayatri]

heyy. When i run the code, after hitting postmapping everything is okay. but after hitting getmapping, my rows are empty. please help

[@Javatechie]

Is data present in your database

[@Prodcater]

In this case will the ouput of the users will be in exact same sequence as it was stored in Db??

[@Javatechie]

Yes

[@benpracht2655]

If I had work that I wanted to split among many threads, not just call a method with a completable future, what would I need to do?

[@indomie6384]

Hello sir, could you please show us how to add other methods like PUT, DELETE, and get by ID?

[@JavaWallah-tp3ue]

please make full video on spring auth2 security with jwt token

[@ahmedahmed-my1iq]

Hi Basant- can you tell us how does the thread knows how to split the work between them when you have not indicated this in your code? wont there be overlapping in performing the task? I see using single thread is as fast or faster than multiple threads.

[@ashoka-thegreat5289]

Thread is not splitting the task, it’s you who are splitting the task and assigning it to different threads. Each time you call an async service method it will be executed on a new thread.

[@ashoka-thegreat5289]

If you found my response helpful or you have any query i can help, you can connect with me on twitter: @biswajitojha430

[@vivviv4497]

For some reason only one thread is getting executed!

[@pradeepmedikonda7282]

There willl be two threads you will trigger.. because the pool size is 2 right.. if you want to check before return you could use some thread sleep then you will find it.

[@kayeshparvez]

What would happen if you call the findAllUsers method 103 times. 2 will be running by two threads. the queue size is 100. so 100+2 = 102 tasks can be handled. What will happen to the 103rd task in this case ?

[@Javatechie]

Queue size meant to hold waiting task in queue Who ever thread serving 101 and 102 request once any one release he will pick 103 task in queue Note : queue will not always full with task , if task executed then it will release from queue and new task will add to queue in FIFO manner

[@kayeshparvez]

@@Javatechie got it now. thanks 😊

[@Cloudy-Moon-z3l]

is this implemntation will work the millions of records?

[@Javatechie]

Yes why not

[@nayan.j]

I am getting FutureTask can not be casted to CompletedFuture

[@Shubham-bb6dr]

i have one question ...in first method of async config class return type in excutor but returns ThreadPoolTaskExecutor...why?

[@Javatechie]

Executor is an interface however ThreadPoolTaskExecutor is it's implementation

[@Shubham-bb6dr]

@@Javatechie it's my mistake actually I import executors which is class that's why I get error

[@dmitrikonnov922]

I'm just having hard time telling difference between ThreadPoolTaskExecutor that we configure and thread pool executor of tomcat server that handles http requests. Are these the same pool?

[@beeam1791]

Hello! I have one noob question, what is the purpose of using this? I've tried the same with sync call and got 353ms for request1 and 117ms for request2, while in async call it has 412ms for both calls

[@ShinAkuma]

This is an IO intensive task so time taken will be more or less the same no matter how many threads you create because records will still be inserted one by one only cause DB has to maintain consistent primary key IDs.

[@beeam1791]

@@ShinAkuma Sorry mate, but I didn't understand, could you please elaborate?

[@bluex217]

​@@beeam1791I've got this 1 so basically what he means is, note that the database has an ID column in the User table, and the id column is the primary key. Primary keys must be UNIQUE, no 2 users can have the same primary key. So, imagine you have 10 threads each inserting some of the users from the list of users sent via the MultiPartFile like in this video, if thread-1 and thread-2 are running concurrently, thread-1 trying to insert a row into the users table for "John Doe", and thread-2 inserting for "Joe Smith", for example, but thread-1 sets John Doe's ID column to value of 1, and thread-2 sets Joe Smith's ID column also to 1, this cannot be, no 2 users can have the same ID. Therefore, the insertion of users must be done sequentially to ensure that no 2 users are inserted with the same ID. You'd likely get an exception if this happened, anyway, because ID columns are intrinsically unique.

[@natetolbert3671]

Why the nested try block in UserService class? Why not just add the catch to the inner block and get rid of the outer? And why all these static methods? I am used to core Java ; it feels like Spring is throwing OOP out the window.

[@ShinAkuma]

I believe the outer try is meant for exception handling while inner try is just meant to avoid writing close() method for the buffered reader.

[@ayushdixit7605]

Hello Sir, I'm able to fetch response in parallel manner. But when I'm applying @Async on saveUser method, I'm getting FileNotFoundExcetion: System can't find the path specified. On Removing @Async from method it's working. Could you please suggest any changes on above issue.

[@CashLootsOfficial]

for using 2 threads itself i am getting output as list of users fetched by get is from thread 3 from where did thread 3 come into picture? i had specified the thread count as 2 only.

[@jayjoshi1366]

If I call different APIs like - getAllUsers(), getUsersById(), getUsersByName(), getUsersByEmail(), getUsersByGender(), and use CompletableFuture along with @Async Config class for ThreadPoolTaskExecutor; then only getAllUsers() is getting called by my custom created thread "userThread-1". But other APIs are called/executed by the Tomcat's threadpool executor http-nio-8080-exec-1. Can you please explain on this, that why other APIs are being executed by the Tomcat's nio executor and not our configured ThreadPoolTaskExecutor. It would be really appreciated as I am very much stuck into this. Thanks in advance _/\_

[@tejasnakhate]

I have one question, in controller when we called findAllUsers multiple times, each time it ran on a new thread. But when we call saveUsers multiple times in the for loop, it does not run in different thread even tough both saveUser and findAllUsers methods are annotated with @Async annotation in service. Why so?

[@Javatechie]

Always recommend to use multi threading in read operation not in write operation

[@tejasnakhate]

@@Javatechie but how does read operation does not go for multiple threads even tough it is annotated with async annotation?

[@bluex217]

@@tejasnakhateYes I not understand why we need to explicitly create several CompleableFuture objects when calling findAllUsers in order for multiple threads to be used but yet for saveUsers we do not need to and @Async annotation is enough for saveUsers but not for findAllUsers

[@i_am_kshitij1118]

How to integrate sleuth, as span I'd is not getting progatated to async method

[@saikumarperamsetty]

video length is too much high🙏🙏🙏🙏

[@akshaynalamwar2257]

Is this work on cluster environment??

[@Javatechie]

Yes why not .

[@teguhep9444]

hi, in the end your video, your endpoint getUsersByThread didn't return result, how to return the result?

[@shobharao3970]

I tried this example today, when I get the users i get 500 internal server. I dont see the USER_TBL created in the H2 DB console. What else has to be done? appreciate it if you can answer.

[@Javatechie]

Did you configure Lombok in your IDE ?

[@shobharao3970]

@@Javatechie I was able to figure out the issue. The problem was not with lombok, it was with H2 DB app properties. I did not configure it, so the DB connection was not made to create the table. But Thank you for replying as fast :)

[@kayeshparvez]

What could I do if I wanted to return the saved names in return of the post request ?

[@somnathchaudhuri8698]

How to stop the thread at the end of the execution, I am getting following error message "Appears to have started a thread name [Asynchread-2] but failed to stop it

[@trinityprogrammer2464]

hello sir video bohat acha he sir ap please chat massenger ka ek video banayen using spring boot or rest api please sir

[@trinityprogrammer2464]

sir ji chat wala kaam hota hua ho please sir

[@Javatechie]

Hi Ashok , Already I uploaded it , created chat application using spring boot websocket example please have a look

[@trinityprogrammer2464]

@@Javatechie thanks sir m zaror dekhonga apka video sir ap spring boot Rest Api security and firewell system security pr bhi ek video banayen sir please

[@Javatechie]

Spring Rest security already available in javatechie please search and grab it