Java 访问私有成员

class Outer_Demo {
   // private variable of the outer class
   private int num = 175;  

   // inner class
   class Inner_Demo {
      public int getNum() {
         System.out.println("This is the getnum method of the inner class:");
         return num;
      }
   }
}

public class My_class {

  public static void main(String args[]) {
      // Instantiating the outer class
      Outer_Demo outer = new Outer_Demo();

      // Instantiating the inner class
      Outer_Demo.Inner_Demo inner = outer.new Inner_Demo();
      System.out.println(inner.getNum());
   }
}