Identify the basic elements of object-oriented programming.

Compare and contrast relations vs. objects.

Explain the concept of dependency injection.

In the following code who is injecting what into whom ? when? why?

@Stateless
@Path("cpdb")
public class CPDBResource {
    @PersistenceContext
    private EntityManager em;

    @GET
    @Path("person/{id}")
    @Produces(MediaType.APPLICATION_JSON)
    public Person getPerson(@PathParam("id") long id) {
        return em.find(Person.class, id);
    }
}