Unknown Entity no Hibernate

Programação Java
#1

Meu java Bean

package br.com.condominio.Model;

import javax.persistence.Entity; 
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Apartamento {

@Id
@GeneratedValue
private Integer id;

private int numero;
private int quartos;
private String ocupacao;

public int getNumero() {
	return numero;
}

public void setNumero(int numero) {
	this.numero = numero;
}

public int getQuartos() {
	return quartos;
}

public void setQuartos(int quartos) {
	this.quartos = quartos;
}

public String getOcupacao() {
	return ocupacao;
}

public void setOcupacao(String ocupacao) {
	this.ocupacao = ocupacao;
}
}

Meu xml

 <?xml version='1.0' encoding='utf-8'?>
 <!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>

	<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
	<!-- A linha abaixo pode ser um endereço ip -->
	<property name="hibernate.connection.url">jdbc:mysql://localhost/bancoapartamento</property>
	<property name="hibernate.connection.username">root</property>
	<property name="hibernate.connection.password"></property>
	<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
	<property name="hibernate.hbm2ddl.auto">update</property>
  
	<mapping class="br.com.condominio.Model.Apartamento" />
    

</session-factory>
</hibernate-configuration>

Meu Session Factory

	private static final SessionFactory sessionFactory = buildSessionFactory();

private static SessionFactory buildSessionFactory() {
	Configuration configuration = new Configuration().configure();
	StandardServiceRegistryBuilder serviceRegistryBuilder = new StandardServiceRegistryBuilder();
	serviceRegistryBuilder.applySettings(configuration.getProperties());
	ServiceRegistry serviceRegistry = serviceRegistryBuilder.build();
	return configuration.buildSessionFactory(serviceRegistry);
}

public static SessionFactory getSessionfactory() {
	return sessionFactory;
}

public static void salvar(Object object){
	
	Session session = getSessionfactory().openSession();
	session.beginTransaction();
	session.save(object);
	session.getTransaction().commit();
	session.close();
}
#2

Encontrei o problema no return do Session Factory que deve ser:
return new Configuration().configure().buildSessionFactory();