02. Equals and HashCode Contract & Different Variations

Рет қаралды 52,315

3 жыл бұрын

This video includes:
- What is default implementation of equals() and hashCode() method.
- What is equals() and hashCode() contract.
- What will happen if we don't follow the equals() and hashCode() contract.
- Side effects of not overriding hashCode() method when equals() is overridden.
- Interview question based on equals and hashCode implementation.
- equals method always returning false & hashCode method returning same value... then what will happen when we put key-value pairs in hashmap.
#java #interviewquestions #webencyclop
In this playlist I will try to cover all the important java interview questions along with answers in very intuitive, kind of pictorial/animated way.
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In this series we will be covering all Java interview questions and answers. This is going to be comprehensive list of Java interview questions which can help experienced Java developers to prepare for an interview as well as upskilling the Java knowledge.
I would always recommend everyone to watch Durga Sir (durgasoft) videos because of extensive in depth explaination on all topics if you have more time.
But here we will try to cover important aspects of Java Programming which are always asked in interviews withing less time.
Interview Questions Answers
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Interview questions and answers
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Пікірлер: 70

@linhpksw 4 күн бұрын

Very clear and through. Thank you so much. Keep doing more!

@KiraTeiubesc 3 жыл бұрын

I have watched like 5 videos on this subject, but it still wasn´t that clear. But you explained everything so clearly and easily that now I get it! Thank you very much 🙏 !

@webencyclop 3 жыл бұрын

Thanks a lot

@rakibullahsarkar1870 2 жыл бұрын

Exactly!

@blinkwit1427 3 жыл бұрын

You have a gift for explain clearly concepts. You should continue :)

@AbhishekKumar-pk3zp Жыл бұрын

For me, this video has the best explanation of hashcode and equals method contract.👍 Worthy to subscribe.

@nikhilbhangale5894 3 ай бұрын

simply great with animation ......

@sanjayranga2683 Жыл бұрын

The best explanation ever .. i think my interviewer saw your video :P

@prasadkondhalkar6499 Жыл бұрын

Most simplified explanation watched till now. Great work.

@ericaugusto5640 3 жыл бұрын

Amazing teaching skills, thank you for this, now i finally understand this concepts.

@rajatagrawal7016 2 ай бұрын

You explained it to me in a very easy manner I have watched many videos but your videos cleared my concepts

@sushiljoshi2326 2 жыл бұрын

He explained very well with his nicely made presentation ! Thanks for this video. Others make this concept complex, he made it simple .

@sourabhgurjar1324 3 жыл бұрын

presentation is really good and simple to understand the concept very well.

@ManishKumar-qx1kh 2 жыл бұрын

we need to make this channel popular by any means. The videos are exceptionally good. Thanks for the hard work brother.

@rahulrsavant Жыл бұрын

Got 10 out of 10 for Explanation, make lots of different videos, using same style, Thanks 🙏

@dnyaneshtathode5511 Жыл бұрын

That's a really good explanation. Clear and concise. Keep it up.

@iwn77620 2 жыл бұрын

Thank you for the effort of visualising it so good. Very clear presentation!

@karandedhiya9575 2 жыл бұрын

Very simple and to the point explanation with beautiful PPT

@sreedharreddy472 3 ай бұрын

well explained sir. It is very clear.

@shivaraju8405 2 жыл бұрын

Seriously a wonderful explanation. watched so many videos but after watching this video there is no requirement of watching other videos. Great Work Man, keep it up . tqsm

@mangesh26 Жыл бұрын

You made my day, I watched dozens of videos and gone through many websites, blogs but not able to get clear understanding. But the way you explained it, it blow my mind. Good Job, keep posting videos

@prashantranjan4859 Жыл бұрын

Excellent.. wonderful explanation.. thanks a ton.

@tanishktripathi217 Жыл бұрын

You earned a subscriber, bro! great explanation, keep doing this!

@mahmoudramadan9193 5 ай бұрын

Great explanation . thank you ♥

@naveenprakash3640 3 жыл бұрын

I usually don't comment....but this is really amazing

@jatinsharma3792 5 ай бұрын

Ahhhh shukariya bhai !!!

@smsms8522 3 жыл бұрын

Excellent Video

@koenasadhu8068 2 жыл бұрын

Wonderful explanation!!

@aniruddhachunne3011 2 жыл бұрын

Thank you so much sir... you are saver .....i spend whole day to understand this concept..

@tunghoang9373 3 жыл бұрын

Thanks from a user from Viet Nam Your explanation was so easy to understand although it's hard to understand your english as much :)

@parleneha25 3 жыл бұрын

Awsome explanation.. Thank you🙏

@hassanmahammad1135 2 жыл бұрын

Wanted to complete java series, hope u get million subscribers and likes

@karthikr8798 Жыл бұрын

You are a LEGEND sir. Thanks for the video.

@rakibullahsarkar1870 2 жыл бұрын

Thank you for clearing my confusion

@knowledgeispower115 3 жыл бұрын

Great explanation

@savaliyaparth468 Жыл бұрын

Great explanation 👍

@anandlshinde 3 жыл бұрын

Good Content / presentation and explaination. Keep it up

@aniketjadhav3503 6 ай бұрын

this same interview question is asked to me in datamaticas but could not able to answer but now I can!!

@pavankalyanmodugu994 Жыл бұрын

The way how u explained awesome great sir make more videos in the same style of explanation &presentation also

@sandeep_khangar 2 жыл бұрын

Awesome video's and pictorial representation ❤️❤️

@sirojiddinsaidov3657 2 жыл бұрын

Very good video. Super

@shraddhawagh9480 2 жыл бұрын

Awesome explanation Sir..... when I watched your videos and went for interviews and explained same which you explained , interviewer really impressed with this ... you deserve million of subscribers Sir... one request can you please make video playlist on one real time project so that it would be beneficial for us ... By using latest technologies like SpringBoot , Microservices, latest angular for frontend Database as oracle DB

@marvellouschandan Жыл бұрын

Awesome explanation bro 😃

@sapnahegde5491 Жыл бұрын

Thanks. Please upload more videos. You make concepts so clear by your explanation.

@webencyclop Жыл бұрын

thank you, sure uploading more soon.

@NKG_Creations 2 жыл бұрын

Excellent Sir, Thanks alot

@naveenvigneshwar5190 10 ай бұрын

Thanks a lot 🙏 💓

@desiengineerashish4908 2 жыл бұрын

The way you explain is wonderful✨ Please make more vdos...🙏👌👏🌻🇮🇳😊🙇

@supriyashrivastava4535 3 жыл бұрын

Explanation is very precise,clean & well documented. Thank you so much sir. Please make a video on java 8 features with implementation.

@webencyclop 3 жыл бұрын

Thanks and sure.

@NeverQuitOk 3 жыл бұрын

KINDLY UPLOAD SOME MORE VIDEOS RELATED TO JAVA INTERVIEW QUESTIONS

@MHK958 Жыл бұрын

Awsome

@webencyclop Жыл бұрын

thank you

@thevagabond85yt 7 ай бұрын

9:12 this chart is OP

@priyamore8582 2 жыл бұрын

It's just like string. N. When we create with new then instance is thre n alm

@GauravVermasadh_raj 3 жыл бұрын

how get operation will work here ?

@PriyankaC-wo8ns Жыл бұрын

sir, "==" checks if both the objects are pointing to same memory location or not and .equals() method compares the values.

@webencyclop Жыл бұрын

yes, that is correct, "==" checks if both the references are pointing to same object or not. If equals() method is not overriden, it will use inherited Object.equals() method, which is same as "==" check. If equals() method is override, then it will be behave as per the code in equals() method, and usually equals method is override in such a way that it compares the content/values of object.

@atulverma.515 3 жыл бұрын

Thanks, Ankit. this is quite a comprehensive video on this topic. A couple of questions came after using the same example. 1. I have created three objects of the student class, st1, st2, st3. with the same values of roll num and name. put s1, s2, s3, and again s1 in the map. but the size of the map is showing as 3 and not 4. however equals always returning false. 2. how come get() method is working, as equals() method in student class is returning false?

@webencyclop 3 жыл бұрын

for first question, from java 8 code, i see java people has added an extra check for object equality viz. if (ref1==ref2 || ref1.equals(ref2) ).. so due to this or condition when same object is added it overwrites.. ( thanks for noticing this. will need to update the same in video) for second question, it's really good question and has been answered on stackoverflow. Please check here. stackoverflow.com/questions/13521184/equals-returns-false-yet-object-is-found-in-map/13521238

@atulverma.515 3 жыл бұрын

@@webencyclop Thank you Ankit for sparing time to clear my doubt. Cheers.

@RishiChopra141 8 ай бұрын

In Student Class you are not overrriding equals but you are overloading it. To Override equals you have to have same method signature first which is public boolean equals(Object object){...}

@SinghRahul- Жыл бұрын

why dont u upload more videos..

@vijayaakkireddy5952 2 жыл бұрын

equals() evaluates to the comparison of values in the objects..If so o1.equlas(o3) should return true right.since == is used for memory reference comparision

@webencyclop 2 жыл бұрын

the default implementation of equals is same as ==

@davidbilla2361 2 жыл бұрын

Why you stopped posting videos?

@jeebanpradhan8050 Жыл бұрын

Bro logical program java please

@pif5023 5 ай бұрын

I would be careful with the first example, it is confusing. The JVM will say o1.equals(o2) not strictly because they point to the same object in memory but because being the same object their fields will be the same by value. The operator to check for identity (exact same object) is == in Java.

@karamjitsinghsehdev3451 Жыл бұрын

But equals method compares the content and not the memory location. 😢

@webencyclop Жыл бұрын

Yes, the equals() method should always compare the contents. But if you don't override the equals() method in your own class, then it takes the default implementation of the equals() method, and that implementation doesn't compare content instead it compares the memory internally.