Inner Classes - General Questions

Which nested type is implicitly static?

What is the output of the following program?

public class Main {
    public static void main(String[] args) {
        int base = 10;
        class Adder { int add(int x) { return base + x; } }
        System.out.println(new Adder().add(5));
    }
}

What is the output of the following program?

class Main {
    private int x = 7;
    class Inner { int get() { return x; } }
    public static void main(String[] args) {
        Main o = new Main();
        Main.Inner in = o.new Inner();
        System.out.println(in.get());
    }
}

How is a static nested class created from outside?

What is the output of the following program?

public class Main {
    interface Greeter { String hi(); }
    public static void main(String[] args) {
        Greeter g = new Greeter() {
            public String hi() { return "hello"; }
        };
        System.out.println(g.hi());
    }
}