Abstract Classes vs Interfaces: Interview Question with a Twist!

The Main difference between Abstract Classes and Interfaces.

I often ask this at the beginning of an interview to establish where a candidate is in terms of computer science knowledge since this is a very simple, foundational question. Here's how I like to think of an answer.

[luisdwq]

I was looking for a while for a direct and clear explanation, and yours really helped, thanks!

[coryandreasen]

awesome video, sometimes something like interfaces vs abstract classes can seem so simple, but its still immensely helpful to hear it spoken out loud and detailed

[jayrao]

Suggestion the background music is a bit distracting.

[riftsassassin]

Love the vid! Thank you for helping the next gen of devs! We appreciate it a lot!

[marat.]

Damn, bro, that’s so fire. I’ve finally found a video about differences between these two buddies. Because everyone who made a blog or a video i watched or googled, they are just telling the difference between code realization, that’s all
Thank you, I highly appreciate your video!

[vincentndivhuwo]

This was very profound way to explain the difference and I found it very helpful and easy to understand

[thegaribovv]

Gabriel, can you make a video about difference between abstraction and encapsulation? I think this is so confusing topic for beginners

[shivamkashyap]

the most logical explanation to the concept around the purpose of interface and Abstract class.

[jetzemeilink]

Incredible explanation. Subbed right away.

[akhilraj-lbxj]

an excellent thought. I was searching throughout blog, but no one tells why is it, and what is the purpose. Thanks a lot Gabriel

[aakashsharma]

Thank you for this video. Although if you could please add some examples to explain this concept or difference between the two, then that would really help.

[salahayman]

why ur videos are so rare hope you add more thanks man

[khizerrehan]

Can you recommend some books to learn OOP ?

[thegaribovv]

Nice video, I watched about 20+ videos and they always speaks same. Bu you explained the twist

[mahmudsharipov]

Thanks, I gues it is the best answer this this question

[udayadi]

Could have been better, if difference was shown in screen clearly

[prerakchoksi]

Note for myself
Summary:-
Abstract Class: To generalize behavior.
Interfadce: To standarize. It is a contract that the object should be having this much things.

Although we can now have methods in both, purpose of the methods in both case is different. Interface methods were interoduced to not break existing implementations.
Also,
All variables in interface are public+static+final while in abstract class thats not the case. So all members of implemented/extended class will have same/different copies in interface/class respectively.


There isnt other difference I think, still feel free to comment and discuss

[RobsonCassianoSoftware]

Fortunately we use that kind of info only on the interview process.

[sayedqandel]

The video is good but it would be better and clearlly if u putted a code example

[izvarzone]

If someone asked abstract class vs interface, I'd say these are completely unrelated concepts.