Generics and Wildcards in Java | Part 1 | Generics with Wildcards in Java Made Simple | Geekific

[@ZenjobBuddyJensJeremies]

Thank you so much for this. The first good explanation of wildcards I have seen so far!

[@kalebnegussie8140]

Well done. I had a question and you answered it 100%. Awesome video. Thanks.

[@geekific]

Glad I did! Happy to help :)

[@DivinityAgarioMore]

You are very good at explaining. For the future, maybe you can look at providing realtime problems and solutions to deepen our understanding further. Other than that, excellent video!

[@geekific]

Thanks a lot, happy you liked it! And great suggestion will keep it in mind for the future :)

[@pavolalmasi3760]

I am so happy that I've found your channel, your videos are super informative and everything is very well explained, keep it up

[@geekific]

Thank you! Glad I could help :)

[@ucanhtran4372]

GREAT EXPLANATION !!!!

[@notsoholyspirit9312]

Extremely helpful video !!

[@geekific]

Glad you think so!

[@manux7739]

thanks for the explanation!

[@innerpeace5877]

you are the best your video saved me ily

[@alvaro1379]

wow this was so well explained thanks for the video!!

[@pedromedeiros8025]

It was very helpful. Great job!

[@geekific]

Glad! Thank you!

[@markconnolly5260]

Great videos. Live them ❤

[@louzexuzhou]

This is gold.

[@geekific]

Thanks a lot! Your words are gold to me :)

[@bluem03]

Why shouldnt i always use Wilcards? and just bound to a specific Type

[@bjugdbjk]

Great and Simple to the point !! One question though, u mean Generics are class wise and wildcards are for Method wise boundaries ? is there any other difference further ..

[@geekific]

Generics can actually be used for methods as well as for classes, when we do so the method is called a generic method, so the type parameter will be tied to the method alone and not the class. However, making use of the wildcard at class level won't really make sense, your code won't compile. Wildcards are used in Java to handle variance, and you can't create a class if you don't know what attributes it defines! We will be covering all these in a part 2 Generics video, stay tuned! Hope this answers your question :) Cheers!

[@coop6734]

Thank you!

[@esoterikouno]

thx, now I understand.

[@geekific]

Glad I could help! :)

[@kakashi99908]

Hello I am remaking data structures to better understand how to use them. Can you explain wild cards used in the class level like this: public class MaxPriorityQueue

[@geekific]

Hello, we will be uploading a video Part 2 that dives in the details of generics and should answer all of your questions regarding this topic! Stay Tuned!

[@ionguzun3952]

nice video

[@lucasf.v.n.4197]

No ? super T explanation thumbs down

[@geekific]

Thanks for the review! However, am not sure what seems to be the problem or which parts of the video weren't clear, can you elaborate so we can fix it?

[@lucasf.v.n.4197]

@@geekific u only explained

[@geekific]

You are right :) We'll be working on a part 2 generics video to expand further on the subject! Stay Tuned! And meanwhile, as a quick answer to your question: 'extends' means that the generic type (?) has to be a subclass of T, however, 'super' means that the generics type has to be a super class of T, in other terms it is T that extends the generic type (T represents the lower bound here). Hope this helps. Cheers!

[@lucasf.v.n.4197]

@@geekific Got it; but when should I be using which? And why in the documentation there are methods that use super? For example, the Stream interface has the method forEach, that takes a "Consumer

[@geekific]

Okay, the fully detailed answer will have to wait for the video, but in short remember PECS (Producer extends, Consumer super). When you are producing or "reading" use extends, when you are consuming or "writing" go for super and if you need both do not use a wildcard just T. They make your code more flexible by allowing the use of subtypes and supertypes when needed. Stay tunned for more details in an upcoming video!