Exemplo Persistence Unit

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="dev" transaction-type="RESOURCE_LOCAL">
		<properties>
			<property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost/aula-jpa" />
			<property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
			<property name="javax.persistence.jdbc.user" value="postgres" />
			<property name="javax.persistence.jdbc.password" value="postgres" />
			
			<property name="hibernate.hbm2ddl.auto" value="update" />
			<property name="hibernate.show_sql" value="true" />
			<property name="hibernate.format_sql" value="true" />
			
		</properties>
	</persistence-unit>
	
</persistence>