Não consigo abrir conexão(Hibernate + GlassFish)

Assuntos Gerais
#1

Eu estou seguindo uma apostila da K19 de integração de JSF e JPA. Mas surgiu este problema:
javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Cannot open connection
Não consigo imaginar o que seja…

persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
	xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
	<persistence-unit name="loja" transaction-type="RESOURCE_LOCAL">
		<provider>org.hibernate.ejb.HibernatePersistence</provider>
		<properties>
			<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
			<property name="hibernate.hbm2ddl.auto" value="update" />
			<property name="hibernate.show_sql" value="true" />
			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
			<property name="javax.persistence.jdbc.user" value="root" />
			<property name="javax.persistence.jdbc.password" value="root" />
			<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/lojavirtualdb" />
		</properties>
	</persistence-unit>
</persistence>

JPAFilter

package filter;

import java.io.IOException;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;

@WebFilter(servletNames = { "Faces Servlet" })
public class JPAFilter implements Filter {

	private EntityManagerFactory factory;

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		this.factory = Persistence.createEntityManagerFactory("loja");
	}

	@Override
	public void destroy() {
		this.factory.close();
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		EntityManager manager = this.factory.createEntityManager();
		request.setAttribute("EntityManager", manager);
		manager.getTransaction().begin();
		chain.doFilter(request, response);
		try {
			manager.getTransaction().commit();
		} catch (Exception e) {
			manager.getTransaction().rollback();
		} finally {
			manager.close();
		}
	}

}
#2

Esse erro tá muito genérico. Copia o stacktrace completo aqui. Normalmente a causa do problema está no “caused by”.

#3

Então… ele nao gerou nenhum log de erro, tanto no console e na pagina

#4