When putting static in front of an implementation (defaulting) method in a Java 8 interface,
presently, it is forbidden to use the keyword default alongside static. Now I now that such
is supposed to default to a new "defaulting" interface method anyway.
Yet by comparison, all Java interfaces are abstract interfaces, yet the Oracle
does not reject an interface declaration with abstract alongside interface.
-default static should at least be compiler allowed in interface methods.
The way things are with non-implementation, non defaulting java 8 interface signatures
is that when there is no visibility modifier specified on an interface method signature declaration,
it seems that (public) gets injected there by java anyway. To the point where implementing
methods in a normal class won't compile unless they specify public. Bear in mind
that the idea seems to be that things get imported from within packages, and that
static imports now exist.
-(no modifier) should be allowed by class methods implementing interface method signatures.
as should (protected).
In interfaces, if interface fields are injected to be final anyway,...
-(final) should be required from source code by the compiler.
and, ...
-(no modifier) and (private) should be allowed by the compiler on final fields in interfaces (all interface fields).