9. Java Memory Management and Garbage Collection in Depth

[@sivakokkiligadda365]

Memory models and Garbage collection is one of the complex topic. But you make it very simple. This is the best explanation ever I have seen. Thank you so much brother.

[@siddhantpardeshi1204]

This is by far the best explanation I've come across on Memory Management. So detailed yet so easy to understand. Thank you so much🙏

[@ConceptandCoding]

Thanks 🙏

[@sasiraj1594]

Great Explanation.. FYI for viewers Default GC for java > 8 is G1GC & parallel GC for java 8

[@PranjaliKhule-i5w]

Very detailed explanation. Love how you dont skip even a minor topic so anyone who's missed a previous video still gets the context.

[@manojrana4469]

bhai shab.....i have nothing to say . just one lector you will clear any interview related to JVM/Heap/GC . Thanks a lot. Just subscribed

[@vishalathawale183]

had never understood this topic before so better. Thanks for such a great explanation. Hats off to your knowledge and way of teaching

[@californiaBala]

not too simple; not too complicated; right way of explaining the most complicated topic; this is good enough for java application developer. you could write a simple Java application; runtime, provide a minimum memory; create a while(true) loop and create several objects; crash the JVM. then you could add random objects set null for garbage collection. also create weak and soft references; observe null pointer exception.

[@parthdalvi5855]

Thank you so much for such a wonderful explanation. This is one of the best explanations to memory management in Java. Clear, simple and easy to understand.

[@whereiskhalid]

Huge shout out for you brother for such a easy explanation. Subscribed ✌🏼

[@saurabhtiwari9614]

Perfect explanation by our beloved "Mr. Perfect bhayiya"😊😊😊

[@ConceptandCoding]

:)

[@ganeshreddy9003]

Bro Thanks a lot Best & best explanation Even a non programmer can understand 👌

[@ConceptandCoding]

thanks a lot

[@Crack4yDream-iz1lm]

@@ConceptandCoding True 100✌🏻

[@altamashalishaikh1612]

Was searching since morning for best videos of memory management and types of gc and now i can say this is the bestest video i got today...so easy and clear explanation ❤

[@shantahiremath7313]

Thank you so much for making us understand the concept so easily.

[@CriticalInsightsRealizations]

a staff engineer for a reason! bro! kudos to this and really well documented and oriented video! Thanks! Good luck! best wishes

[@PrjBh]

Awesome video man. Just to point out one trivial thing, in Mark phase of Mark & Sweep, it marks all the referenced nodes( not the unreferenced ones) from the root( active thread, or any static variable) and subsequently in sweep phase the unmarked ones get deleted, just like having only one connected component from the root.

[@LeahThomas-is4hm]

thanks a lot....was very helpful..no one explains this much simply ....great content also

[@pranavkhatri30]

Wow, just wow. Overwhelmed.

[@ConceptandCoding]

thanks

[@MOHAMMADBILAL-hz6fq]

The best video I found so far on memory management. 🎉

[@vijaymaradkar]

Best explanation I have ever seen for Memory Management

[@AbdelrhmanAdel-y3b]

thank you that is the most insane playlist in java i have ever seen

[@ConceptandCoding]

thanks

[@abhidattabaral8321]

One of the best explanation on java memory till date, Even paid courses has never taught us this things..Thank you @Concept && Coding - by Shrayansh.

[@siddhantprakash.]

Learnt so many new things today! I will flaunt these knowledge in my upcoming interview as an fresher :)

[@rahathasan5971]

How to be a member

[@KamleshMore-pn3ds]

Extremely informative and interesting. Thanks!

[@rupeshpatil6957]

Great Explanation on Memory Mgmt. Thanks Brother

[@yelururao1]

First of all thanks for your time and doing videos. Will comment again after watching video

[@ConceptandCoding]

Sure

[@mansisengar9282]

Mind blowing explanation on Java memory management ! 😊

[@ConceptandCoding]

thanks

[@SouradipChandra]

This is really awesome. Thanks for breaking down Java Memory Management and Garbage Collection so clearly!

[@ConceptandCoding]

thanks

[@ganavin3423]

thanks Shrayansh..u explained nicely .

[@kanikadeka3106]

Nice explanation. It's really pretty much informative content which is helpful to understand memory related behavior of your application during load test. Thank you so much for such detailed explanation.

[@SomjitNag]

FYI, Weak reference can be useful when implementing caching, as it is something we can afford to loose, and by nature, is designed to be refreshed.

[@SomanathMikali-h5x]

Bro best and clear explaination:), just loved the way you teached!

[@rohan8758]

Just Wow! It's amazing sir

[@AryanKapoor0711]

Mind-blowing content! The way you clear concepts is simply amazing! 🙌

[@ranendas73]

Wow - such a nice and simple way explained....you are doing great services, thanks

[@husniwfayo8450]

Best explanation for Memory Management , thanks broo really helped a lot

[@Akshaystudy-r8n]

Great video ! Thanks for the effort .

[@Rameez-Raja]

Thanks for your great explanation.. Simple and crispy 🎉🎉

[@lakshyabhardwaj2146]

This is a great explanation 👏 thank you sir

[@sreelakshmij189]

Bro u nailed it.. Just hit a like for this vedio.. And im gonna learn java the way i wanted to learn here... Tq sooo much for this vedio.

[@nettion]

Such a good explanation. Thanks for this

[@Do_ItForAnime]

Hey, where did you get all this knowledge from: books or working in corporate?

[@vasanth_here]

1000th Like, Thanks sir for this quality content.

[@KishoreThatavarthi]

Hi Shreyansh Jain At 33:48 i have one doubt when mark & sweep ran second time why it put obj6 directly into S1 and Why not S0 . Can you please explain

[@ConceptandCoding]

Hi, the decision of whether object is placed in S0 or S1 during the Young Generation collection is determined by which Survivor space was used Last. If an object survives one cycle in S0, it will be moved to S1 in the next cycle and vice versa.

[@satyamsc]

Grt Explanation Bro!. keep it up! :) Thanks a lot

[@shreyabag64]

thank you so much sir😊 this helped me a lot for my exams.

[@WealthyManiacOG]

Hi Shreyansh, I have a doubt, you told during Mark & Sweep with Compaction that the objects will get stored in sequential order after gc works but won't that be everytime as the surviving objects are put into Survivor space? So, why would it put in random memory locations in the first place, it should be sequential for any kind of mark & sweep, right?

[@dep2460]

Mark and sweep with compaction is generally for old generation where fragmentation can occur

[@knowledgeascend]

Great Video! Thanks.

[@ConceptandCoding]

Thanks

[@pooja.sahu95]

wow😍 amazing explanation

[@kunalthunderwave]

Hi I have few questions, can you please ans those: 1) which algo is used in serial gc, parallel gc and g1 garbage collector? 2) does compaction happens in serial, parallel?

[@nettion]

I’d be nice to have another video explaining how to tune the JVM, the different use cases for the JVM parameters. And maybe another video on jvm profiling and analisies

[@krishnendughosh2368]

33:30 why obj6 is put into s1 and not in s0? Who decides where to put it?

[@amartyabasu9552]

I suppose, its get selected alternatively. If first batch goes in s0, second batch will go in s1. Mentioned in video also, after few second of what timestamp you marked.

[@narendrajangid11]

thanks a lot to clearing the consept completely

[@LokeshSharma-hm5jz]

Q- How garbage collector knows that any memory occupied in heap has no reference? Is there any internally hapmaps used to which garbage collector has access.

[@SonuSharma-fc9hd]

Nice explanation❤

[@GarlapatiAyyappaLokesh]

i got a doubt that as per the video you mentioned that threshold age 3 whenever the surveyor objects reaches age 3 it promotes to old gen ,what if we haven't provided anything threshold value then what is default age by JVM. Thanks advance

[@bhuvanakuppusamy6933]

Neat explanation 😊

[@israelmathusse7100]

The best explanation

[@amzabdrahim3350]

bro, thank you so much. you are a life saver!

[@LaptopBackup-bo6kp]

Hi shreyansh, is there any way to check data values inside heap when running a java program

[@athul03]

33:09 Why obj6 is going into S1 rather than S0?

[@kunalthunderwave]

This was a great explanation of GC. Can you please make videos on lastest versions of garbage collection as there are many updates on these after Java 8. Thanks😃

[@NanditaBharadwaj]

15 years back, when I was working on a java application, we used to get outofmemory error and not stackoverflow ... can you please talk about the differences? do they have outof memory any more... thank you for this video... you know your topic... I appreciate it... thanks

[@abrahamlincoln5724]

Stack overflow error occurs when stack space has reached its limit. One of the cause is a recursive algorithm with no or incorrect base cases. Out of memory error - When heap space has reached its limit. Causes can be too many unintentional reference holding of objects, GC can't sweep enough dead objects and running frequently, too many class variables to load in the perm gen of heap space etc.

[@nishantsharma6435]

How many years of experience do you have ?

[@NanditaBharadwaj]

@@nishantsharma6435 I have nearly 6 years of exp from long back in Java and J2EE tech

[@richat946]

Now what are you doing

[@sdash2023]

Sir, that's a very neat and clean explanation of memory structure and garbage collection. I have studied so many articles and checked so many videos but never got this much of clarity. But could you please explain G1 gc and some memory optimization techniques in second part. We are getting a lot of follow up questions from memory optimization section which I have no idea of. sir... please please please bring a second part with these two sections.....

[@ConceptandCoding]

Thanks a lot. Sure will do

[@learnpromax1]

​@@ConceptandCodingAny update or eta on 2nd part of memory management and GC?

[@tejass5060]

Hi Shreyansh, A quick doubt here, you were explaining about Mark & Sweep with compact algorithm right. You said that once the algo finds that the memory used to store objects in not sequential then it will make the objects store in sequential order right? My question is will the reference name change in that case, what I mean is if you try to print the object without having toString() then it will print @sdf23 will this change?

[@tejass5060]

Any update on this @Shreyansh?

[@rajatmehta7545]

@Shreyansh waiting for answer.

[@ChandanKumar01784]

No, the reference name will not change when a mark-and-sweep algorithm with a compacting step is used to store objects in sequential order

[@justClip_GossipGal]

best explanation ❣

[@sreeharipullasetty8632]

Great explanation

[@--SaikrishnaR]

wow wonderful explanation . thank you

[@Earn-Ccr]

Hey there! Absolutely loved your explanation, how can I get the notes shared by you on the screen ???

[@HimanshuSingh-ti6qw]

Great end to end now i got it ❤

[@skeditz1952]

Sir there is a doubt about the reference if two variable is referenced to a single object means is it a strong reference or a weak reference

[@abhijeetbagde1597]

Thanks! Very helpful

[@TheOne-cy3yu]

In mark , sweep and compact algo, u r referring to memory blocks inside eden, s0, s1 ? or as a whole in the heap..?

[@vivekbhore5722]

its very very interesting, thanks a lot

[@ashutoshroy1234]

i have a question that does String pool values collected by GC? what i read it is safe from GC. Please correct me if i am wrong.

[@SDeepRudra]

Hey Shrayansh, Can you please explain about completablefuture in java8 and flux in spring boot too?

[@MrSanthoshs88]

Just want to say Thank you.

[@DileepV-on7wk]

It's very clear and loved ..what about METASPEACE

[@Anubhav__Code]

I am not able to find memory management notes on the membership page can anyone provide me the link?

[@ManjeetKaur-y1y]

Hi Shreyansh, my question is why we will get out of memory in premgen memory if objects are there in either young an old?

[@SEmadeEASY]

Thanks for this indepth video Shreyansh. Can you also cover about memory leak and possible ways to handle it

[@keeplearning6]

Thank you @ConceptandCoding for the awesome video. Can you please mention the references used for the video, any books, links that you have read for creating this video?

[@PiyushGhosh-l4k]

we give survivalRation:7 what does 7 here means ??? And whats metaSpace ?? How to calculate the set of values which needs to be use to these jvm parameter ???

[@vivekbansal-bc9eg]

best explanation thanks a lot sir!!

[@aniketmahangare8333]

Thanks for the great session Shreyansh. Can you also please share the notes.

[@ConceptandCoding]

will add in description buddy

[@aniketmahangare8333]

@@ConceptandCoding thank you

[@LOVEPREETSINGH-ft6nd]

Great explanation. i just want to know where in the heap will be string constant pool , is this in the old or young generation, is pool a single chunk of memory something else ?

[@kadavakallurajapeddanna5384]

Is it possible to perform GC on String constant pool??

[@khushbusoni8179]

hi Shreyansh Thanks for verfy informative video .i have one query the threshold by default 3 or we can change it

[@praveshrawat9270]

Good explaination

[@santoshbhatnagar2155]

One question why doesn't heap memory removes the object similar to the stack when the method gets over, is it because the way heap memory is implemented?

[@ConceptandCoding]

the heap requires more complex management compare to stack because objects can persist beyond the scope of the method that created them. Thats one of the reason i can think of why similar strategy like stack is not used.

[@instamusic7918]

Notes are not getting download which are on zoho notebook.

[@amangupta288]

sir , i think at 33:39 , during sweep operation obj6 should be first move to s0 with age 1 instead of moving to s1. please do check .. and thank you for making these videos on java it really helps me alot.

[@amangupta288]

sorry time is 33:07

[@akarshkumarsrit2518]

so we have 3 kinds of memory space for a java program - stack,heap and metaspace?

[@DileepV-on7wk]

yeah ,what about metaspace ??

[@Allrounder-13029]

I have a doubt how finalize method will work before GC?

[@ibrahimshaikh3642]

There was method area also which use to store class info, is it same as permanent generation

[@rakhipurwar2575]

Please provide the notes also. Would be easier for us to revise.

[@sachinmukherjee29]

@Shreyansh Can you share the notes link also if possible?

[@ConceptandCoding]

will try to create and update in description section

[@ammanmoini1202]

Is there any difference between reference variable and reference of object?

[@ashwani_kumar90]

very basic explaination, could please discuss in more depth of grabage collections on generation part. How we can switch in b/w of existing GC during the runtime of application.

[@ConceptandCoding]

noted

[@ashwani_kumar90]

thanks , because during interview discussion , they ask in depth on this topic. @@ConceptandCoding

[@rr45creation86]

sir, if no need of system.gc() then why this method and when we use the method....? (garbage collection is done by jvm na)....

[@ConceptandCoding]

Generally this method gives a hint to the JVM that, hey you can start the garbage collector now. But its on hands of JVM when to run garbage Collector. So it doesn't provide the guarantee that even after developer invokes the method, that gc will run just after this method.

[@rr45creation86]

@@ConceptandCoding if don't invoke this method manually is it invoked implicitly ???

[@ConceptandCoding]

@@rr45creation86 consider Garbage collector as a daemon, which runs periodically implicitly

[@omkarshendge5438]

ngl I wanna become a java god tbh, i have dedicated this whole month to learn java and java only alongwith some lld. Many told me not to learn java and everyone around me hated it but still i went on this journey ,10 videos in and im loving java ngl tbh just because of a mentor like shrayansh! Next aim is to learn spring boot after this hehe

[@ConceptandCoding]

thanks a lot buddy and good luck with your learning journey.