abstract interfaces

[Razvan]

Hi !






In a Java test I noticed code like:

abstract interface IDummy
{
// ......
}

This should trigger a compiler error. Interfaces are abstract
by definition. It is pointless to define an abstract one. Am I right
or not ?





Regards,
Razvan

 

[Michael Borgwardt]

In a Java test I noticed code like:

abstract interface IDummy
{
// ......
}

This should trigger a compiler error. Interfaces are abstract
by definition. It is pointless to define an abstract one. Am I right
or not ?

No. Why should the compiler complain about an explicit declaration of
something that's already given implicitly? It's pointless but does no
harm and some people may consider it to improve clarity.

You're also allowed to explicitly declare interface methods public.

 

[Daniel Bonniot]

Note that "abstract interfaces" is a concept in itself (although it's not
present in Java): http://c2.com/cgi/wiki?AbstractInterface

Cheers,

Daniel

 

[Mike Schilling]

Hi !






In a Java test I noticed code like:

abstract interface IDummy
{
// ......
}

This should trigger a compiler error. Interfaces are abstract
by definition. It is pointless to define an abstract one. Am I right
or not ?

It is pointless, but it's allowed. Likewise, interface methods can be
declared abstract and public, even though these keywords are also redundant.
I suspect one can also say:

class A
{
static interface I { }
}

even though the interface obviously has no enclosing member..

 

[Mike Schilling]

Note that "abstract interfaces" is a concept in itself (although it's not
present in Java): http://c2.com/cgi/wiki?AbstractInterface

Thanks for the reference. That's something I often want to do.