JPA + CDI : @Inject EntityManager as a @RequestScoped bean

EntityManagerProducer.java

import javax.enterprise.context.Dependent;
import javax.enterprise.context.RequestScoped;
import javax.enterprise.inject.Produces;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Dependent
public class EntityManagerProducer {
    @PersistenceContext(name = "persistence-unit")  // name is Persistence Unit Name configured in persistence.xml
    private EntityManager entityManager;

    @Produces
    @RequestScoped
    EntityManager createEntityManager() {
        return entityManager;
    }
}

EntityManager is not thread-safe.

This code snippet guarantees a new EntityManager is created/injected for each request.

Usage:

@Inject
EntityManager entityManager;