What is the difference between an abstract class and an interface? i want to know why use the abstract class

Question

Under what circumstances is the abstract class used?

I do not think you need to use an abstract class.

interface is more useful than abstract class

but Why use the abstract class even though the interface is more convenient

what version of Java are you talking about? – Scary Wombat Oct 19 '18 at 07:03 — Scary Wombat, Oct 19 '18 at 07:03
What are the two middle sentences? Are they quotes? – bogl Oct 19 '18 at 07:07 — bogl, Oct 19 '18 at 07:07
@GergelyBacso Hmm, is that link out of date? – Scary Wombat Oct 19 '18 at 07:11 — Scary Wombat, Oct 19 '18 at 07:11

score 0 · Answer 1 · answered Oct 19 '18 at 07:35

Well, they are two separate ideas that could be implemented for the same effect.

Interfaces are contracts, they don't have any behavior defined inside of them, they only provide the method signature, which have to defined elsewhere in the program. You can inherit them and then add your implementation of the methods provided.

Abstract classes, however, are actual classes, with written methods in it. When you inherit them, you already have some sort of behavior defined in the functions.

That's the tl;dr of abstract classes vs interfaces

What is the difference between an abstract class and an interface? i want to know why use the abstract class

1 Answers1