Get single email id ldap

package com.ldap;

import java.util.Properties;

import javax.naming.Context;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.SearchControls;
import javax.naming.directory.SearchResult;
import javax.naming.ldap.InitialLdapContext;

public class GetSingleEmailIDFromLDAP {

	public static void main(String[] args) {
		Properties prop = new Properties();
		prop.put(Context.INITIAL_CONTEXT_FACTORY,
				"com.sun.jndi.ldap.LdapCtxFactory");
		prop.put(Context.PROVIDER_URL, "ldap://domainname:portnumber");
		prop.put(Context.SECURITY_PRINCIPAL, " domainname \\username");
		prop.put(Context.SECURITY_CREDENTIALS, "password");

		try {

			DirContext ctx = new InitialLdapContext(prop, null);
			SearchControls searchControls = new SearchControls();
			searchControls.setSearchScope(SearchControls.SUBTREE_SCOPE);
			String ldap_search_context = "ou=Associates,dc= domainname ,dc=companyname,dc=com";
			NamingEnumeration answer = null;
			answer = ctx.search(ldap_search_context, "samaccountname=userid",
					searchControls);
			while (answer.hasMore()) {
				SearchResult sr = (SearchResult) answer.next();
				Attributes attributes = sr.getAttributes();
				Attribute mailID = attributes.get("mail");
				if (mailID != null) {
					System.out.println(mailID.get());
				}

			}
			ctx.close();
		} catch (NamingException ex) {
			ex.printStackTrace();
		}
	}

}