内部类奇怪的问题

class outer{
    private int size;
    
    class inner{
        void dosuff（){
            size++;
            system.out.println（"the size value of the outer class: " + size);
        }
    }
}

public class testinner {
    public static void main（string[] a) {
        outer out = new outer（);
        outer.inner in = out.new inner（);//声明并创建内部类对象
        in.dosuff（);
    }
}