Java Generics Tutorial

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  • Опубликовано: 9 фев 2025
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Комментарии • 303

  • @KeepOnCoding
    @KeepOnCoding  4 года назад +19

    ☕Want to master Java? Get my complete Java course: bit.ly/42mQlXE

  • @KnakuanaRka
    @KnakuanaRka 4 года назад +130

    Also, something else to add about generics:
    If you’re expecting some specific property of the class you put into a generic, you can write that into your generic. For example, if your class had an array of T’s that you wanted to sort, just putting MyClass will make your compiler complain that you’re doing something unsafe.
    This is because you can only use sort() on the array if the class T implements the Comparable interface and its compareTo() method, and there’s no guarantee someone won’t try to make it with some class Java doesn’t know how to compare or sort (like a custom one).
    The solution here? Write your class header as MyClass. This tells the compiler that you will only make MyClass’es with types that can be sorted. This uses “extends” as opposed to the “implements” usually used for interfaces because you’re just making a promise about the generic class, not actually implementing one, and the second T is because Comparable is also generic (so you need to say that T implements a method to compare T objects specifically).

    • @eustachybakielka
      @eustachybakielka 4 года назад

      It's not because of reification of arrays?

    • @KnakuanaRka
      @KnakuanaRka 4 года назад +1

      @@eustachybakielka Not sure what you’re referring to.

    • @eustachybakielka
      @eustachybakielka 4 года назад

      @@KnakuanaRka "For example, if your class had an array of T’s that you wanted to sort, just putting MyClass will make your compiler complain that you’re doing something unsafe"

    • @KnakuanaRka
      @KnakuanaRka 4 года назад +1

      @@eustachybakielka What the heck is reification of arrays?

    • @eustachybakielka
      @eustachybakielka 4 года назад +1

      @@KnakuanaRka What is reification in Java?
      In the context of Java as a programming language, reification is the process by which a user program or any aspect of a programming language that was implicit in the translated program and the run-time system, are expressed in the language itself. In Java, there exist "reifiable types" that are "completely available at run time" (i.e. their information is not erased during compilation).
      Example:
      //Allocates an array of type String, so it is reified
      String[] aStringArray = new String[10];
      //Allocates a list with no type, Java does not reify generic types
      List aStringList = new ArrayList();

  • @lindawisebear
    @lindawisebear 4 года назад +157

    This is the best explanation of Generics I've seen on the internet. I loved how you started with the problem to solve, and then showed how generics is useful when tackling that problem :)

  • @philippebaillargeon5204
    @philippebaillargeon5204 4 года назад +43

    I like the way you explain things: Java developers created Generics to solve a problem, so I think its pretty logical to talk about the problem before talking about the concepts that were created to solve it. Great video !

    • @mastershonobi110
      @mastershonobi110 3 года назад +1

      Super great point(illustrate the problem to solve, before the concept). A lot of Java Channels should be taking notes!!

    • @angledcoathanger
      @angledcoathanger 2 года назад

      Totally agree - it's hard to get excited about a key if you haven't seen the lock that it opens

  • @deeptimonga7375
    @deeptimonga7375 4 года назад +40

    Keep On Making such videos on Keep On Coding channel. Really Helpful !!

  • @TS-wj4im
    @TS-wj4im 3 года назад +2

    Dude thank you. My text book way over complicated generics. Now it all makes sense.

  • @abdullahmajed7554
    @abdullahmajed7554 4 года назад +1

    that was really simple i love the way you edit the video making switch between you and the code it feels so clean, thank you

  • @conea6891
    @conea6891 3 года назад +1

    I like this fast paced explanation.

  • @IgorBeneli1014
    @IgorBeneli1014 4 года назад +1

    You're incredible you explained with 12min a concept that my professor couldn't do it with 1 hour. Keep doing this amazing job thank you so much!

  • @shagiwan
    @shagiwan 2 года назад +1

    Second year of studying Software Development in Uni and this is just the best explanation ive heard! Great job man!

  • @chinemelumj5349
    @chinemelumj5349 2 года назад

    Finally understood generics, thank you so much!.

  • @101matthias
    @101matthias 4 года назад +6

    I just watched 9 hours of online classes from my teacher on generics and I understood nothing. Less than nothing. 10 minutes of you and everything is clear it's super easy actually.

    • @technocoh
      @technocoh 2 года назад

      yeah not every professional or teacher is able to share his knowledge the proper way... ;)

    • @pinolskun8764
      @pinolskun8764 2 года назад

      @@technocoh yeah if someone need 9 hours to explain a concept you can safely assume they are the first who don't understand it

  • @mohannadfadhal4282
    @mohannadfadhal4282 3 года назад +3

    Thank you so much, Sir. You made the explanation for generics very simplified, especially, by the style of starting with the problem first and then showing the solution! 🤩

  • @JosephGallagher
    @JosephGallagher Год назад

    This is the most concise and easy to understand video I've seen so far on Generics, thank you so much :D

  • @dalvandi
    @dalvandi 4 года назад +6

    Possibly one of the best, clearest, and crispest explanations on the generic class that I've seen! Keep up the great content dude!

    • @ramiayash7658
      @ramiayash7658 3 года назад +1

      i highly agree with you, the guy is so clear with his explanations

  • @himanshushukla787
    @himanshushukla787 3 года назад

    bro your java playlist is so underrated. I love it

  • @BoetFly
    @BoetFly 4 года назад +19

    Man, thank you so much, i finally understand those generics now :D

  • @philyeo
    @philyeo 3 года назад +1

    awesome stuff. I liked the way you explained it - showing the problem first and how generics can help save the day!

  • @lazpz617
    @lazpz617 2 года назад

    This video really helped me understand Generics way more than my instructors classes

  • @delmayank
    @delmayank 4 года назад +1

    Lounge Coding! I really liked the theme. A new touch to coding tutorials. I am your fan now. You rock! Oh! And the stuff that you covered in this tutorial is of great value. You explained it easily and flawlessly.

  • @earl0fBronze
    @earl0fBronze 4 года назад +1

    I read a thirty page chapter on this, one ear out the other. This video is outstanding, mind blown.

  • @ravenmadd1343
    @ravenmadd1343 3 года назад +2

    Why can't everything be explained this clearly and quickly?
    Thanks for doing this and keep up the good work.

  •  3 года назад +2

    Wow! You explained it all so good. I finally feel like I understand this. Thank you so much. Please keep it coming.

  • @fredericoamigo
    @fredericoamigo 2 года назад

    Thank you so much for this! I love your Java tutorials. So simple, clean and explanatory. Keep up the good work!

  • @sheriffcrandy
    @sheriffcrandy 4 года назад

    You seem like just a solid dude haha thanks for the help man!

  • @SaljooqAltaf
    @SaljooqAltaf 4 года назад

    This just might be personal preference but the best and most detailed explanations for anyone studying comp sci are found in this channel - no idea why views haven't hit a million

  • @gauravkumarsingh640
    @gauravkumarsingh640 4 года назад

    This is legit the best video I could find to understand Generics!

  • @kaifahsan8459
    @kaifahsan8459 4 года назад +1

    Thanks for the video mate. Pretty well explained.
    Would be awesome if you keep making videos about core and advanced OOP concepts like this.

    • @KeepOnCoding
      @KeepOnCoding  4 года назад

      Thank you sir. Did you have a specific topic in mind?

    • @kaifahsan8459
      @kaifahsan8459 4 года назад

      Probably topics like interfaces, polymorphism, exceptions, collection frameworks etc.
      There's a huge Quora thread that might help you as well:
      www.quora.com/What-is-a-complete-list-of-topics-of-Core-Java-and-topics-of-Advanced-Java

    • @KeepOnCoding
      @KeepOnCoding  4 года назад

      Awesome! Thanks!

  • @hannahc8436
    @hannahc8436 2 года назад

    This was such a great explanation of Generics. I've been so confused about it for the past few weeks. Thank you!!

  • @alexmedina5135
    @alexmedina5135 4 года назад

    what a good, easy, and elegant way to explain generics ... keep it up!!

  • @PrakashVl
    @PrakashVl 4 года назад

    This tutorial is helpful for filling the gaps in generics, thanks for explaining thoroughly.

  • @isah.2980
    @isah.2980 3 года назад +1

    Thank you so much! Please, keep doing videos like this!

  • @jiwonskitsch
    @jiwonskitsch 4 года назад +1

    Thank you for this quick video. You saved me 30 minutes of reading long paragraphs from my lecturers.

  • @KeepOnCoding
    @KeepOnCoding  4 года назад +18

    Have you ever used Generics in your code?

    • @Jilnn
      @Jilnn 4 года назад +1

      nope

    • @Chaz-LeeP
      @Chaz-LeeP 4 года назад +2

      yea! coming from c++, i was taught that its called templates

    • @ActualVital
      @ActualVital 4 года назад +2

      Yup. My Data Structures professor would always require us to use them. Still don’t understand them. Hopefully this video will help me understand!

    • @guitarman813
      @guitarman813 4 года назад +4

      Yes, in my latest Java project. While they seem easy in theory, implementing them is another matter! I hope to gain knowledge from this video and other sources and thus strengthening my performance in this area.

    • @rossocorsa6577
      @rossocorsa6577 4 года назад +3

      Keep On Coding Yee for my assigment

  • @wovasteengova
    @wovasteengova 4 года назад +1

    This looks like it's from java, a beginner's guide. I too was confused on what generics fix but thank you for explaining it in the beginning of the video. I think you should do that to all your videos

  • @prabhakarlal4799
    @prabhakarlal4799 4 года назад +1

    Nice and simplified explanation of a complicated topic. Thank you.

  • @shreypatel9379
    @shreypatel9379 4 года назад

    This was the best explanation on youtube, short and concise. Thank you and keep making such videos

  • @athardaif
    @athardaif 4 года назад +1

    I was struggeling with understanding generics until I watched your video. Thanks a lot :)

  • @anx007d
    @anx007d 3 года назад

    Thank You very much .. after looking many videos from different sources ....... this video absolutely cleared my thoughts for Java Generics.

  • @19sunheart96
    @19sunheart96 3 года назад +1

    Nice video! Very easy to understand explanation of the concept.

  • @ziekaman2450
    @ziekaman2450 3 года назад

    Thankyou so much. You're very talented in explaining complicated Java thingys!

  • @youvegotmail9385
    @youvegotmail9385 2 года назад

    Not sure why it's still taking me a minute to wrap my head around Generics. I'm sure it'll click, but it's so funky to me even with your great explanation.

  • @AshBeastreal
    @AshBeastreal 3 года назад

    Wow this is one of the best explainer videos. Loved watching it🤩

  • @CarlosRamirez-uz7hs
    @CarlosRamirez-uz7hs 3 года назад

    Great video man, keep doing what you do

  • @quikel7045
    @quikel7045 2 года назад

    Watched 2 videos, had it at uni, read documentation and still didn't understand why Wildcards are useful. You basically explained it in 2min with a simple example. Thank you very much.

  • @2010aishwary
    @2010aishwary 4 года назад +1

    very nice to the point video, subbed

  • @monetoast
    @monetoast 4 года назад +1

    Exceptional video, very clear!

  • @abdullahmoiz8151
    @abdullahmoiz8151 4 года назад +6

    Man this was a fantastic explanation
    I particularly liked how you first showed what the problem was then showed how generics solve it

  • @leonrickert4061
    @leonrickert4061 4 года назад +2

    Keep on man, cool teaching style

  • @tarunkaushik320
    @tarunkaushik320 4 месяца назад

    Very well! Nice explanation of usages of Generic types, and Wildcards.👌(helps in understanding the difference between them and their significance)

  • @saintfrancisbeats9639
    @saintfrancisbeats9639 4 года назад +1

    Dope! I am currently in an Intermediate Programming college course and they just want us to read a document. I was so lost. This clarified alot. Also it cause me to switch from Netbeans to IntelliJ IDEA hahaha

  • @morolillyshean8816
    @morolillyshean8816 2 года назад +1

    Yes, this is the best one I found. Thanks!

  • @zachhewitt4328
    @zachhewitt4328 4 года назад +1

    10/10 man! Keep it up. It's better than my current professor!

  • @ledtargaouschi5831
    @ledtargaouschi5831 4 года назад

    Your videos are very helpful and your teaching methods are very clear

  • @RubenGarciaCS
    @RubenGarciaCS 3 года назад

    Excellent quality! Thank you

  • @abhijeetmokale9024
    @abhijeetmokale9024 4 года назад

    Seriously this way of learning from the problem is amazing! Thanks Sir!!

  • @fahadtahir6
    @fahadtahir6 4 года назад

    Very informative and loved your communication style

  • @olegc6209
    @olegc6209 4 года назад +1

    Awesome explanation, thanks for your help!

  • @tetsuorulin9009
    @tetsuorulin9009 3 года назад

    I love teaching to the problem. Great video and thanks!

  • @davidxdhloqud
    @davidxdhloqud 2 года назад

    I'm spanish speaker, your videos are sooo good than I can understand, thank you

  • @shecodesthings3978
    @shecodesthings3978 4 года назад

    Ah, another example of my previous compsci professors failing to teach something fairly straightforward... *facepalm*
    You, on the other hand, taught it in such a practical and applicable manner: Discuss a simple problem and then propose a solution (and actually working through the example)
    Super easy to remember too. Great video!

  • @damyandimitrov611
    @damyandimitrov611 4 года назад +1

    Very well explanation and approach

  • @89pravinb
    @89pravinb 3 года назад

    Thank you for creating this video! Very concise and informative

  • @faikyesilyaprak8761
    @faikyesilyaprak8761 4 года назад +1

    That was lit bro!!!! Thanks for crystal clear explanation :))))

  • @anithachowdary9716
    @anithachowdary9716 4 года назад

    I understood the topic very well.Thank you so much Please share more videos

  • @aavocadoToast
    @aavocadoToast 3 года назад

    Great video! Detailed and to the point.

  • @qwarlockz8017
    @qwarlockz8017 3 года назад

    Nice video. You do have a great way of explaining things.

  • @tolstoievski4926
    @tolstoievski4926 3 года назад

    You can also declare generic type at method scope id you're planning to use static methods (methods that are not requiring you to instantiate class to use it)

  • @lurkhidden9126
    @lurkhidden9126 4 года назад

    Learned hella! Good looks my guy

  • @TKollaKid
    @TKollaKid 3 года назад

    Great explanation - clear and helpful. Thank you.

  • @leeamraa
    @leeamraa 8 месяцев назад

    correction: you should make this function type-bounded as well, like this --> "boolean absEqual(NumericFns

  • @leslyp.blaise7238
    @leslyp.blaise7238 3 года назад

    Explanation clear and concise thank you

  • @nisarullah7734
    @nisarullah7734 3 года назад +1

    Great work keep it up

  • @premalupadhyay3555
    @premalupadhyay3555 4 года назад

    Great and simple explanation, I like this way of teaching a lot.

  • @kylemanley915
    @kylemanley915 4 года назад

    Sweet tutorial, just subscribed

  • @liaskarllate
    @liaskarllate 4 года назад

    WOW' You're good at teaching code and concepts. Way to go!

  • @999loaderu
    @999loaderu 3 года назад

    really well explained m8. Appreciate it. thx

  • @Burak-cr6um
    @Burak-cr6um 2 года назад

    Thank you, It was very helpful as usual.

  • @nikeshparajuli6345
    @nikeshparajuli6345 4 года назад +4

    it's really helpful,thanks a lot .

  • @ItsTheDannyShow
    @ItsTheDannyShow 4 года назад +1

    Subscribing man. You helped so much.

  • @okikiomisande8732
    @okikiomisande8732 2 года назад

    Awesome explaination, thank you!

  • @lancelotlin3459
    @lancelotlin3459 4 года назад

    Best tutorial! Thanks for your explanation!

  • @dablo898
    @dablo898 4 года назад +1

    Thank you, I learnt something new today

  • @chikken007
    @chikken007 4 года назад +1

    Great explanation! Just gained a new Sub. Thank you and keep it up please!

  • @pratikthorat3480
    @pratikthorat3480 3 года назад

    I know what generics are but I still feel I learnt a few new things here. God Dayummm you are awesome.

  • @xxanton8xx
    @xxanton8xx 4 года назад

    You look like you're gonna fall asleep the next second, but you explained the topic very well!

  • @brownyeet3981
    @brownyeet3981 4 года назад +2

    Holy shit THANKS!

  • @bibahbibah5108
    @bibahbibah5108 3 года назад +1

    i like the u develop the subject, uake java very easy to work with

  • @ritexcorp
    @ritexcorp 2 года назад

    That was a great explanation of Generics, keep up the good work, I just subscribed to your channel. Do you have something on Java annotations?

  • @himangshuchowdhary4369
    @himangshuchowdhary4369 2 года назад

    Great explanation KOC!

  • @kalyanmatamarugu9396
    @kalyanmatamarugu9396 4 года назад

    Clean, simple and perfect content!

  • @timo_b3
    @timo_b3 4 года назад

    Thank you, excellent explanation!

  • @toniiicarbonelll287
    @toniiicarbonelll287 4 года назад +1

    MAAAAAAAAAAAAAAAAAN that was just awesome thank you very much!

  • @donwinston
    @donwinston 8 месяцев назад

    You didn't cover generic methods and the parameter type lists before the returned type in a method definition. I've been using generics for years and just learned this today! Don't have to use this when you're just a consumer of generic classes.

  • @GeorgeKonstantinou-v2i
    @GeorgeKonstantinou-v2i 3 года назад

    well thank you for explaining to me what i didn't learn from the class.

  • @arnabmukherjee5840
    @arnabmukherjee5840 4 года назад +1

    Awesome tutorial bro

  • @xsendilien9551
    @xsendilien9551 4 года назад +1

    Really awesome bro!

  • @tamimjabr1648
    @tamimjabr1648 4 года назад

    You are awesome bro, thank you for this video

  • @porkfreegaming5278
    @porkfreegaming5278 3 года назад +1

    You are awesome! thank you good sir

  • @VishnuSunilkumar
    @VishnuSunilkumar 3 года назад

    perfect. That deserves a thumbs up.