public class Outer {
  private int outProp = 8;
  class Inner {
    private int inProp = 5;
  }

  public void accessInnerProp() {
    System.out.println(new Inner().inProp);
  }

  public static void main(String[] args) {
    Outer p = new Outer();
    p.accessInnerProp();
  }
}

只是提示一下，外部类可以访问内部类的所有，只不过需要借助内部类对象