public class Main {
    public static void main(String[] args) {
        System.out.println("Hello world!");
        Out.In in = new Out().new In("内部类");
        Out out = new Out();
        Out.In in1 = out.new In("内部类1");


        SubClass subClass = new SubClass(out, "内部类子类");

        Out.testIn.print("测试内部静态类");
        Out.testIn testIn = new Out.testIn();
        testIn.println("测试静态内部类");
    }
}