개요[ | ]
- HR자바 Can You Access?
Java
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import java.io.*;
import java.lang.reflect.*;
import java.util.*;
import java.util.regex.*;
import java.security.*;
public class Solution {
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
Java
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//Write your code here
Class inner = Class.forName("Solution$Inner");
Class priv = Class.forName("Solution$Inner$Private");
Constructor con = priv.getDeclaredConstructor(inner);
con.setAccessible(true);
o = con.newInstance(inner.newInstance());
Method method = priv.getDeclaredMethod("powerof2",int.class);
method.setAccessible(true);
System.out.println(String.valueOf(num)+" is "+method.invoke(o,num));
Java
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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);
}
}
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