How to define two persistence units (one for production, one for unit testing)?

Question

This is my stateless bean:

@Stateless
public class Finder {
  @PersistenceContext(unitName = \"production\")
  EntityManager em;
  [...]
}

Answer 1

You can create a second persistence unit in your configuration, but that doesn't necessarily mean you should. Multiple PUs are of course entirely right and proper, but I'd steer clear of mixing them up when they're specifically for different environments, e.g. production versus test.

In your instance, I'd have two persistence configuration files, and have Ant / Maven / build tool of choice copy / rename the correct one when appropriate.