How to get DataSource or Connection from JPA2 EntityManager in Java EE 6

Question

I have a working application where I use Java EE 6 with EclipseLink for persistence and a PostgreSQL database.

For the User-Registration I want to set the password i

Answer 1

sometimes it just takes another run in google:

entityManager.getTransaction().begin();
java.sql.Connection connection = entityManager.unwrap(java.sql.Connection.class);
...
entityManager.getTransaction().commit();

as described in the Eclipse Link Documentation