@NamedQuery(name = "User.Test", query = "SELECT u.testBoolean FROM User u WHERE u.userName = ?1"),
...
@Column(name = "testBoolean")
    private Boolean testBoolean = false;

Query query = em.createNamedQuery("User.Test");
        query.setParameter(1, "testuser");

        try {
            result = (Boolean) query.getSingleResult();
        } catch (NoResultException e) {
            result = null;
        }