Java generics with class and nested static interface

Question

I want to use a generic class inside a nested static interface. My objective is to do something like this:

public class MyClass{
    private MyInter         


        

Answer 1

It's not redundant. With a static interface:

MyClass.MyInterface myInstance;

and with a non-static innter class (an interface is always static):

MyClass.MyInterface myInstance;

A more real world example:

Map map = ...;
for (Map.Entry entry : map.entrySet()) {
    ...
}

The static approach has the advantage that you can import the nested type, and still specify the type parameters:

class ClassWithAReallyLongName {
    static interface Entry {
    }
}

and

import my.package.ClassWithAReallyLongName.Entry;

class Foo {
    Entry bar;
}

though one should use that idiom with caution as to not confuse the reader.