Error: Exception in thread "main" org.hibernate.MappingException: Unknown entity: com.hibernate.demo.model.Contact

package com.contact;



import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileLock;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

import com.contact.model.Contact;

public class Application {

    //Session factory
    private static final SessionFactory sessionFactory = buildSesssionFactory();

    public static void main(String[] args) throws InterruptedException {

        System.out.println("Session factory");
        Contact contact = new Contact.ContactBuilder("Bob", "Marley").withEmail("bob.nik@gmail.com").withPhone(5859789733L).build();

        //Open a Session
        System.out.println("Open a Session");
        Session session = sessionFactory.openSession();

        //Begin a Transaction
        System.out.println("Begin a Transaction");
         session.beginTransaction();


        //Use the session to save the contact
        System.out.println("Use the session to save the contact");
        session.save(contact);
        //Commit the transaction
        System.out.println("Commit the transaction");
        session.getTransaction().commit();
        // Close the session
        System.out.println("Close the session");
        session.close();
    }

    private static SessionFactory buildSesssionFactory() {
        // Create a StandardServiceRegistry
        Configuration configuration = new Configuration();
        configuration.addAnnotatedClass(com.contact.model.Contact.class);
        configuration.setProperty("hibernate.temp.use_jdbc_metadata_defaults","false");
        configuration.configure();

        final ServiceRegistry registry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
        return new org.hibernate.boot.MetadataSources(registry).buildMetadata().buildSessionFactory();


    }

    static boolean isLocked(String fileName) {
        try {
            RandomAccessFile f = new RandomAccessFile(fileName, "r");
            try {
                FileLock lock = f.getChannel().tryLock(0, Long.MAX_VALUE, true);
                if (lock != null) {
                    lock.release();
                    return false;
                }
            } finally {
                f.close();
            }
        } catch (IOException e) {
            // ignore
        }
        return true;
    }

}