Is it a feature abuse to introduce default methods in new interfaces?
daniel.fuchs at oracle.com
Thu Feb 21 14:54:41 UTC 2019
I don't think this is an abuse, and I'd say that the decision on
whether to provide a default implementation for a new interface
probably depends on how well you estimate that the default
implementation will match what concrete subclass would have to
implement. Even if that's not an authoritative answer ;-)
I don't know if that's representative but Stream.Builder for
instance, came with a default add( ) method:
On 21/02/2019 14:35, Jaikiran Pai wrote:
> I have been trying to find some authoritative answer on when _not_ to
> use default methods on interfaces (a feature introduced in Java 8). The
> official documentation in Java, about this feature, talks about the
> motivation behind introducing this feature and explains how
> _existing_ interfaces can be changed to add default methods without
> breaking binary compatibility:
> "Default methods enable you to add new functionality to the interfaces
> of your libraries and ensure binary compatibility with code written for
> older versions of those interfaces."
> This and some other docs don't mention whether it's an accepted practice
> or abuse of default methods feature, when dealing with new interfaces.
> Is it fine to introduce new interfaces with default methods? I have
> tried searching the mailing list archives to see if it's discussed
> previously but my search terms haven't found anything relevant. Any
> previous authoritative answer, similar to Stuart Mark's reply on
> stackoverflow (on a different topic) about Optional usage, is also
> good enough.
>  https://docs.oracle.com/javase/tutorial/java/IandI/defaultmethods.html
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