Problema na criação de tabelas com o Hibernate

org.hibernate.MappingException: An AnnotationConfiguration instance is required to use <mapping class="com.jeovane.sistema.cliente.Cliente"/>
Exception in thread "main" java.lang.NullPointerException
	at Conecta.main(Conecta.java:10)

<hibernate-configuration>
 <session-factory name="">
  <property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property>
  <property name="hibernate.connection.password">vertrigo</property>
  <property name="hibernate.connection.url">jdbc:mysql://localhost/sistemavendas</property>
  <property name="hibernate.connection.username">root</property>
  <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
  <property name="hibernate.hbm2ddl.auto">update</property>
  <mapping class="com.jeovane.sistema.cliente.Cliente"/>
  <mapping class="com.jeovane.sistema.produto.Produto"/>
  <mapping class="com.jeovane.sistema.venda.Venda"/>
 </session-factory>
</hibernate-configuration>

public class Conecta {
	public static void main(String[] args) {
		Session session = null;
		try {
			session = HibernateUtil.getSession().openSession();
			System.out.println("Conectou!");
		} finally{
			session.close();
			System.out.println("Fechou a conexão!");
		}
	}
}

public class HibernateUtil {
	private static final SessionFactory session = buildSessionFactory();

	private static SessionFactory buildSessionFactory() {
		try {
			Configuration cfg = new Configuration();
			cfg.configure("hibernate.cfg.xml");
			return cfg.buildSessionFactory();
		} catch (Exception e) {
			System.out.println("Erro!\n" + e);
			throw new ExceptionInInitializerError();
		}
	}

	public static SessionFactory getSession() {
		return session;
	}
}