Public defender methods and static inner classes in interfaces?

[Pavel Minaev]

On Mon, Sep 13, 2010 at 7:03 PM, Jim Mayer <jim at pentastich.org> wrote:
> Currently interfaces have a well defined purpose: they specify a contract
> without an implementation.  That's a simple concept to get across and the
> language enforces it.

Unfortunately, it is too simple for many practical purposes. It's no
surprise that most "Java++" languages (e.g. Scala) go even further,
all the way towards traits.

> interfaces were introduced, I assume, because of
> the widespread concern about multiple inheritance.  Defender methods raise
> the same issues as multiple inheritance

Issues with multiple inheritance are primarily when inheritance of
state is involved, which is not the case with defender methods.