What is a static interface in java?

Question

I was reading through the Map.Entry interface, when I noticed it is a static interface. I didn\'t quite understand what a static interface is, and

Answer 1

I'm curious about the case when it's not an inner interface.

The static modifier is only allowed on a nested classes or interfaces. In your example Entry is nested inside the Map interface.

For interfaces, the static modifier is actually optional. The distinction makes no sense for interfaces since they contain no code that could access the outer this anyway.