Java Interview Questions and Answers for Fresher and Experienced [MOST ASKED ] Code Decode

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  • เผยแพร่เมื่อ 24 พ.ย. 2024

ความคิดเห็น • 154

  • @CodeDecode
    @CodeDecode  3 ปีที่แล้ว +26

    Hey Guys, These are the Questions which we face mostly in the first round of Giant MNC's like Infosys, Accenture,Amdocs , Deloitte, IBM etc
    If you have faced any other questions please comment down below we will cover that in next part.

    • @akashkeshari8927
      @akashkeshari8927 3 ปีที่แล้ว +1

      For what experience range, these questions are asked?? Fresher level??

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +2

      0-6 years. First round / telephonic / skype / Teams

    • @srijith431
      @srijith431 3 ปีที่แล้ว +11

      I have experienced few more questions like
      1) what is CI/CD ?
      2) internal working of hashmap
      3) what is bean creation exception ?
      4) and some questions like how to commit in git.
      5) and about junit

    • @srijith431
      @srijith431 3 ปีที่แล้ว +1

      @@CodeDecode but I don’t think wipro , IBM , Accenture , Infosys are conduction telephonic rounds.

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      By telephonic we meant teams, skype, google meet, etc. And in covid situations, yes they are. Are you able to go to office to give interview? Because our team couldn't

  • @javier.alvarez764
    @javier.alvarez764 2 ปีที่แล้ว +14

    1. LinkedList vs ArrayList?
    - arraylist better for storing, linkedlist better for manipulating data (insert, update, delete).
    2. Lazy initialization
    - only fetch data when needed.
    3. Difference between first level and second level cache in hibernate
    *1st level
    - by default enabled
    - associated by Session
    - when session gets close your cache gets lost
    - only accessible by the session that maintains it.
    *2nd level needs to programmatically enabled
    - associated by SessionFactory
    - accessible to whole program
    4. HashMap vs HashTable
    HashTable
    - synchronized
    - thread safe
    - does not allow null key or null value.
    HashMap
    - not synchronized
    - not thread safe
    - only allows 1 null key
    - can be synchronized using Collections.synchronizedMap(hashMap);
    5. What is Java Garbage Collection?
    -
    6. What is Serialization?
    - converts object into byte stream to transmit data.
    7. What is Dependency Injection or Inversion of Control?
    - instantiation is handled by the framework.
    8. What is WeakHashMap?
    -
    9. What are functional interface?
    - only has one abstract method, but can have multiple default and static method.
    - use as reference to lambda expression.
    10. Why is there concurrent hash map if synchronized map already exist?
    - performance issue in synchronized map.
    - SynchronizedMap acquires lock on the entire Map instance , while ConcurrentHashMap divides the Map instance into multiple segments and locking is done on those.
    - ConcurrentHashMap is therefore faster because of these.

  • @nvjrane
    @nvjrane 3 ปีที่แล้ว +17

    This seems like a short 15 min video, but the study behind it must be so deep to have your concepts clear and present it concisely to us. I have never learned so much in the last few months that I learned in this short video. Keep it up!

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +2

      Yes that's very true Nitish. Thanks for recognizing our efforts and putting that up in such a nice words 🙂👍👍. Thanks a lot 👍👍

    • @ashisdalai5369
      @ashisdalai5369 2 ปีที่แล้ว +1

      Lucky we get it in 15 min

    • @virendra872
      @virendra872 ปีที่แล้ว

      ​@@ashisdalai5369 AA

  • @usamaansari7903
    @usamaansari7903 3 ปีที่แล้ว +6

    i always prepare more with defination but while giving interview I could not able to ans what I had learned word to word just like u..u r giving word to word ans...this much of confidence and concentration I want as a fresher

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Thanks Usama 🙃👍👍👍

    • @addminblaze
      @addminblaze 3 ปีที่แล้ว +1

      I dont think anyone wants you to give word to word answer, rather knowing concept and working principles will help. You can use analogies to explain concept, PS: dont over do it.
      You can explain it in your words and thats all needed to crack the interview.

  • @handleOfASK
    @handleOfASK 3 ปีที่แล้ว +19

    It’s like you know all my doubts and you are clearing one by one😂. Awesome… Thank you 😀

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +2

      Thanks 🙂🙂

    • @handleOfASK
      @handleOfASK 3 ปีที่แล้ว +1

      😄😁.
      One request please make a video on..
      Java Memory Management in depth.

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +3

      th-cam.com/video/EeRFOVMf7rE/w-d-xo.html

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      There are 2 parts, it covers memory management in java

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      th-cam.com/video/bu12JCTeWOo/w-d-xo.html

  • @pranjalrathod8556
    @pranjalrathod8556 3 ปีที่แล้ว +10

    Can we have multiple mock up interviews like this please? Your contents are really one of the best out there 🙏

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Sure. We will continue this series. Don't worry 😊

  • @Truth_12349
    @Truth_12349 ปีที่แล้ว +1

    These kind of videos are very helpful to brush up concepts before interviews.

  • @mrunalinimistry6621
    @mrunalinimistry6621 3 ปีที่แล้ว +3

    just hats off to you @Code Decode team. Really helpful. Love from gujarat

  • @SanatanBelievers
    @SanatanBelievers ปีที่แล้ว +2

    13:57 That's very nice question was epic🤣

  • @vinodkarathiyaofficial
    @vinodkarathiyaofficial ปีที่แล้ว

    It was amazing. Request you to make detail video on Garbage Collection.

  • @srashmitha8953
    @srashmitha8953 3 ปีที่แล้ว +1

    Found very helpful ,Please Write Explanation in description ,like your previous videos..!

  • @veena618
    @veena618 3 ปีที่แล้ว +2

    Request you to please keep written explaination in description as you were doing in earlier videos it will help us to have quick round of glance.

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Sure Veena. But we usually go out of space in description, hence couldn't cover all.

    • @veena618
      @veena618 3 ปีที่แล้ว +1

      @@CodeDecode okay no issues👍

  • @dynamicdeveloper6658
    @dynamicdeveloper6658 2 ปีที่แล้ว +1

    All videos are amazing
    Great informative

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      Thanks a lot 🙂👍

  • @kazaasekhar
    @kazaasekhar 3 ปีที่แล้ว +1

    happy to watch it again and again

  • @mohamedely3987
    @mohamedely3987 ปีที่แล้ว +1

    You are doing a great job 👏

  • @akshayengineer2018
    @akshayengineer2018 2 ปีที่แล้ว +1

    You are Amazing... Thank you so much mam 😊

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      Thanks Akshay 🙂👍

  • @AshishSharma-mf4sg
    @AshishSharma-mf4sg 3 ปีที่แล้ว +1

    you are going good🤩
    Just need to add some basic questions which was tricky and even basics .. that would help in interview

  • @akaashkumar4926
    @akaashkumar4926 3 ปีที่แล้ว +4

    Hi Mam, Great work! Can you please make separate playlist on Spring Boot Microservices?
    Now a days Spring Boot means they are expecting microservices as well to be known!
    Please do consider this request

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      So true Akaash. Will surely do that👍

  • @shobhitagarwal8151
    @shobhitagarwal8151 3 ปีที่แล้ว +4

    Hey, I really liked all the questions you choose. All of them are very good questions. Explanation of garbage collector working is too knowledgeable.
    Hoping another great video for round 2. More power to you guys.👍

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Thanks Shobhit 👍we will create soon 👍

  • @kaushikigoel759
    @kaushikigoel759 2 ปีที่แล้ว +1

    This video is gold!!!

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      Thanks for the nice words kaushiki

  • @anilmaurya55
    @anilmaurya55 3 ปีที่แล้ว +1

    Very helpful, please keep the good work thanks

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      you're welcome anil

  • @vamseedhar2482
    @vamseedhar2482 3 ปีที่แล้ว +2

    Good stuff and excellent explanation

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Thanks Vamsee 👍👍

  • @coderdostayush2032
    @coderdostayush2032 3 ปีที่แล้ว +3

    Mam your explaination is just like 3 idiot movie ❤️. Thank you so much for making our journey so easy. God bless you❤️

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      Thanks for the motivation Ayush 👍

  • @sureshgarine
    @sureshgarine 3 ปีที่แล้ว +1

    nice explanation madam. thank you

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Thanks Suresh 👍

  • @vasundharasannidhi5210
    @vasundharasannidhi5210 3 ปีที่แล้ว +2

    This is very helpful. Thank you. Please do for experience level interview also.

  • @abiultimate
    @abiultimate 2 ปีที่แล้ว +1

    Awesomeness 👌 👏

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      Thanks Abirami 🙂👍

  • @vry2652
    @vry2652 2 ปีที่แล้ว +1

    great videos , it could be more helpful if you show snippets code while giving response

  • @scrppr8270
    @scrppr8270 3 ปีที่แล้ว +2

    Great..nicely explained...
    Can you please make similar video on Multihreading concepts...specially Concurrent API

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Sure. We have 2 videos on multi threading. Will create more on concurrency

    • @scrppr8270
      @scrppr8270 3 ปีที่แล้ว +1

      Yes saw those 2 videos...they are also too good😎...but some concepts are to be covered....please cover those as well🙏

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Sure. We will cover them soon 👍👍

  • @GAGamingLegends
    @GAGamingLegends 3 ปีที่แล้ว +2

    Love your videos, please upload more ❤️❤️❤️❤️❤️❤️❤️

  • @anuhyabolla7891
    @anuhyabolla7891 3 ปีที่แล้ว +1

    can you make interview questions on core computer subjects?

  • @karthikeyanrm3446
    @karthikeyanrm3446 3 ปีที่แล้ว +1

    It would be good if you can make more videos on Spring core concepts & interview questions - DI, IOC, Autowiring etc. Also any other important concepts in Spring

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      Sure Karthikeyan we will make it soon....

  • @ashishpal5446
    @ashishpal5446 3 ปีที่แล้ว +1

    Always giving out best content ✨
    Thank you very much for this!!

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Thanks Ashish 🙂👍

  • @vemulasoumyasri830
    @vemulasoumyasri830 3 ปีที่แล้ว +1

    Nyc explanation mam thank u soo much mam waiting for more videos mam🙏🙏

  • @start1learn-n171
    @start1learn-n171 2 ปีที่แล้ว +1

    TQ

  • @muralikommuru5992
    @muralikommuru5992 3 ปีที่แล้ว +1

    Its really great and really covers a lot of concepts, I mean it’s kind of go to if you have less time for preparation, your videos. I would surely look forward for more videos and also will like to suggest you if you can make videos on advanced stream operations for example group by with having, partitioning by, etc as they have overloaded methods with different numbers of parameters and really there is less content related to this outside, which explains each method variant need with examples. It will be nice to watch those videos if you can try them as well.

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      That's a very nice suggestion Murali. Will surely do that 👍🙏

  • @uvanana.
    @uvanana. ปีที่แล้ว +1

    Your videos all good, try to talk a bit slowly .,otherwise your videos are awesome

    • @CodeDecode
      @CodeDecode  ปีที่แล้ว +1

      Sure ❤️❤️👍👍 we will reduce the pace👍

  • @SaahilShaikh
    @SaahilShaikh 3 ปีที่แล้ว +1

    great video 🙌

  • @anjalijaiswal1750
    @anjalijaiswal1750 3 ปีที่แล้ว +1

    One question mam - How Garbage collector knows it is a unused object?

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      If no references are found that means object is unused.
      Object o1 = new Object ;
      O1 is a reference. If I do o1 = null then no reference exists.

  • @Manu-et6zk
    @Manu-et6zk 3 ปีที่แล้ว +2

    Answer to dependency injection question was like : "dependency injection only happens/used in spring applications", and its main advantage was not at all mentioned.

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Dependency injection happens in angular too. It's constructor injection in angular.

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      We will cover all of them Manu, in 15 minutes we tried our best to deliver the most. We know that your time is precious. 🙏but we can't cover every thing in 15 minutes. Thanks for your patience and for your suggestions 👍👍🙏🙏🙏🙏

  • @Ravikumar-nf2mu
    @Ravikumar-nf2mu 3 ปีที่แล้ว +1

    can u make a video about microservices interview questions

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      we will make it soon

  • @soumyakantpani9923
    @soumyakantpani9923 2 ปีที่แล้ว +1

    Hey Guys,Could you just make a vedio of annotations in spring and rest?

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      Hi saumyakant we have created 2 videos on annotations please check that out

  • @start1learn-n171
    @start1learn-n171 9 หลายเดือนก่อน

    Tq

  • @shrutikorke2368
    @shrutikorke2368 3 ปีที่แล้ว +2

    Make interview questions on rest api

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Sure Shruti. Next we will create on them too. We will include restful web services too

  • @gokulaher2476
    @gokulaher2476 3 ปีที่แล้ว +1

    ConcurrentHashMap in java internally uses
    a new more sophisticated technic calles as segment , number of active threads doing write/update operations is == number of Segments, each bucket in HashMap is belong to one segment and
    In ConcurrentHashMap Lock is striped and only that segment is getting lock on which write/update operation is performed
    So multiple write operations can performed by multiple threads on multiple segments concurrently
    Because now Lock is on segment level and not on entire HashMap

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      Thanks for explaining it again Gokul 👍👍🙂🙂

  • @soumyakantpani2997
    @soumyakantpani2997 2 ปีที่แล้ว +1

    can you just make vedio about spring batch?

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      Sure Soumyakant 🙂👍

  • @GaneshSingh1
    @GaneshSingh1 3 ปีที่แล้ว +1

    Do you have any pdf Or ppt stored in gdrive? If you have please share the link So that we can directly download the answers, it will so fast for the revision.

  • @codenexa1666
    @codenexa1666 3 ปีที่แล้ว +1

    At fresher level they will ask this type of questions like spring, hibernate ?

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Yeah these are very basic questions of spring hibernate. They might ask you. Because java is just a language, spring hibernate are frameworks. You might use them in your college major projects 👍👍

  • @nikhilsharma-kd4pi
    @nikhilsharma-kd4pi 3 ปีที่แล้ว +1

    For which profile these questions are for??

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Java full stack developer. Currently this first video has only JAVA questions.

  • @vrushalifasate2052
    @vrushalifasate2052 3 ปีที่แล้ว +1

    Employee object is stored in arraylist .How to sort entities store in object like name ,I'd .

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Collections. Sort(l, customComparatorObj)

  • @arijitmohapatra147
    @arijitmohapatra147 3 ปีที่แล้ว +1

    Mam can u help me where to learn adv java plsss 🙏

  • @usamaansari7903
    @usamaansari7903 3 ปีที่แล้ว +1

    this is for freshers ??

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      For any one trying for java profile

  • @Ravikumar-nf2mu
    @Ravikumar-nf2mu 3 ปีที่แล้ว

    what is the difference between named query and native query

  • @madhu56236
    @madhu56236 3 ปีที่แล้ว +1

    Can I know your experience

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      We are a team of IT people having experience varies from 2-8 yrs

    • @madhu56236
      @madhu56236 3 ปีที่แล้ว +1

      Oh that's great thanks to you and your team🙏

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      👍👍🙏🙏

    • @jithendrareddym9149
      @jithendrareddym9149 3 ปีที่แล้ว

      @@madhu56236 entha experience??

  • @muraliram2582
    @muraliram2582 9 หลายเดือนก่อน

    you are laughing when you are giving the garbage collection answer

  • @amitdubey2793
    @amitdubey2793 2 ปีที่แล้ว +1

    Too many ads, makes this beautiful video annoying.

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      Not in our hands much Amit. It's TH-cam who fits ads in between.

    • @amitdubey2793
      @amitdubey2793 2 ปีที่แล้ว +1

      @@CodeDecode can understand. Kudos for your work 🎊. I have my interview today on java and referring only your channel.

    • @CodeDecode
      @CodeDecode  2 ปีที่แล้ว

      All the very best Amit. We wish You rock in your interviews Man. Keep learning keep Shining 👏👏👏👏🤞🤞

  • @srijith431
    @srijith431 3 ปีที่แล้ว +2

    Good one 👏🏻 also please post some scenario based Q & A which most often asked in interviews 🙏🏻 also please let me know your instagram id

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      Thanks Sri .......
      Instagram : instagram.com/codedecode25/

    • @srijith431
      @srijith431 3 ปีที่แล้ว +1

      @@CodeDecode thank you so much incase of any doubts in subjects it okie to contact thru instagram ?

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว +1

      Sure Sri. You can any time reach us. We are always here for you👍

    • @srijith431
      @srijith431 3 ปีที่แล้ว +1

      @@CodeDecode thank you team 🙏🏻

    • @CodeDecode
      @CodeDecode  3 ปีที่แล้ว

      🙏🙏👍👍