编译外部类时静态嵌套类的.class文件不能通过关联使用，但可以通过继承使用。 为什么？

Question

I have an outer class and a static nested class as

class Outer {
  static int x = 20;
  static class Nested {
    static void show() {
      System.out.println(x);
    }
  }
}

on compiling this program ,I've got two .class files named: Outer.class and Outer$Nested.class .

Now my question is ,I am trying to use the Outer$Nested.class in my other class Test1 (using association).

class Test1 {
  public static void main(String... args) {
    Outer$Nested i = new Outer$Nested();
  }
}

It gives me compile time error : can't find symbol Outer$Nested. And I know we can use static nested class directly as Outer.Nested, but I am just trying this. But when I am trying to use this class via Inheritance then it is compiling and running fine.

class Temp2 extends Outer$Inner {
  public static void main(String... args) {
    show();
  }
}

Now compiling and running fine , output : 20

So my question is why it is happening that we aren't able to use Outer$Nested via association and event we can't declare variable , but can use via inheritance ?

Answer 1

I didn't know how the inheritance concepts works like your way, but want to create instance of the inner nested class use this lines of codes

  public static void main(String[] args){
    Outer.Nested obj= new Outer.Nested();
    obj.show();
 }