HackerRank Can You Access? in java problem solution

In this HackerRank Can You Access? in java problem solution you are given a class Solution and an inner class Inner.Private. The main method of class Solution takes an integer  as input. The powerof2 in class Inner.Private checks whether a number is a power of . You have to call the method powerof2 of the class Inner.Private from the main method of the class Solution.

HackerRank Can You Access? in java problem solution.

if(num<1||num>Math.pow(2,30))
    throw new Exception();

Solution.Inner ob=new Solution.Inner();
Class<?> c = Solution.Inner.class.getDeclaredClasses()[0];
Constructor<?> constructor = c.getDeclaredConstructor(Solution.Inner.class);
constructor.setAccessible(true);
o = constructor.newInstance(ob);
Method m = c.getDeclaredMethod("powerof2",new Class[]{int.class}) ;
m.setAccessible(true);         
String ans = (String) m.invoke(o,num);
System.out.println(num+" is "+ans);