Getting LDAP Response Controls

import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.NamingEnumeration;
import javax.naming.directory.SearchResult;
import javax.naming.ldap.HasControls;
import javax.naming.ldap.InitialLdapContext;
import javax.naming.ldap.LdapContext;

public class Main {
 public static void main(String[] argv) throws Exception {
 String url = "ldap://localhost/o=JNDITutorial";
 Hashtable<String, String> env = new Hashtable<String, String>();
 env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
 env.put(Context.PROVIDER_URL, url);
 env.put(Context.SECURITY_AUTHENTICATION, "simple");
 env.put(Context.SECURITY_PRINCIPAL, "userDN");
 env.put(Context.SECURITY_CREDENTIALS, "secret");

 LdapContext ctx = new InitialLdapContext(env, null);

 NamingEnumeration answer = ctx.search("ou=People", "(cn=*)", null);

 System.out.println(ctx.getResponseControls());

 while (answer.hasMore()) {
 SearchResult si = (SearchResult) answer.next();
 if (si instanceof HasControls) {
 System.out.println(((HasControls) si).getControls());
 }
 }
 System.out.println(ctx.getResponseControls());
 }
}