Can a class extend an abstract class and implement an interface at the same time? (java)

Question

If I have for example a class Foo and also an abstract class Bar and an interface Fizz, can the class implement both in its declaration? Or should the interface first be implemented in the abstract class?

I ask because of this UML Chart: (! the unfilled arrow should point to the abstract class to show that its inherited from the abstract class !)

public class Foo extends Bar implements Fizz {
   ...
}

Is my class declaration correct?

Your UML only shows a dependency from `Foo` to `Fizz`. Nothing else. — qwerty_so, Jul 18 '18 at 05:51
Yes. And Thomas is right -- you probably mean a Realisation rather than a Dependency between Foo and Fizz. — muszeo, Jul 18 '18 at 07:50

score 1 · Answer 1 · answered Jul 17 '18 at 16:21

1

Yeah you can. The only thing you can't do with class declarations is extend multiple classes.

answered Jul 17 '18 at 16:21

Pieter Mantel

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1

Well, that's not the _only_ thing you can't do. Come on now, use your imagination! :) – mypetlion Jul 17 '18 at 16:42
@mypetlion well if you only look at extending classes and implementing interfaces, it is (I believe) – Pieter Mantel Jul 17 '18 at 16:49
You cannot do `implements Fizz extends Bar` ;) – Thiyagu Jul 17 '18 at 17:01
You also can't extend final classes or `extends Enum` (directly, at least). – mypetlion Jul 17 '18 at 17:09
@user7 true forgot about the order :P – Pieter Mantel Jul 17 '18 at 17:38
@mypetlion I said thats the only thing you can't do when extending _classes_, so that still holds true. – Pieter Mantel Jul 17 '18 at 17:39

Can a class extend an abstract class and implement an interface at the same time? (java)

1 Answers1