Can You Access HackerRank Solution

/**
 * 
 */
package com.javaaid.hackerrank.solutions.languages.java.advanced;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.security.Permission;

/**
 *
 */
public class CanYouAccess {
	public static void main(String[] args) throws Exception {
		DoNotTerminate.forbidExit();

		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			int num = Integer.parseInt(br.readLine().trim());
			Object o;// Must be used to hold the reference of the instance of the class
						// Solution.Inner.Private

			// Inner i= new Inner();
			// Private p=new Private();
			/**main code starts from here*/
			CanYouAccess.Inner si = new CanYouAccess.Inner();
			o = si.new Private();
			System.out.println(num + " is " + ((CanYouAccess.Inner.Private) o).powerof2(num));
			/**main code end  here*/

			System.out.println("An instance of class: " + o.getClass().getCanonicalName() + " has been created");

		} // end of try

		catch (DoNotTerminate.ExitTrappedException e) {
			System.out.println("Unsuccessful Termination!!");
		}
	}// end of main

	static class Inner {
		private class Private {
			private String powerof2(int num) {
				return ((num & num - 1) == 0) ? "power of 2" : "not a power of 2";
			}
		}
	}// end of Inner

}// end of Solution

class DoNotTerminate { // This class prevents exit(0)

	public static class ExitTrappedException extends SecurityException {

		private static final long serialVersionUID = 1L;
	}

	public static void forbidExit() {
		final SecurityManager securityManager = new SecurityManager() {
			@Override
			public void checkPermission(Permission permission) {
				if (permission.getName().contains("exitVM")) {
					throw new ExitTrappedException();
				}
			}
		};
		System.setSecurityManager(securityManager);
	}
}