2. Remove Objects

private void removeTowns() {
        this.entityManager.getTransaction().begin();

        List<Town> towns = this.entityManager.createQuery("FROM Town", Town.class).getResultList();

        towns.forEach(e -> {
            if (e.getName().length() > 5) {
                this.entityManager.remove(e);
            } else {
                e.setName(e.getName().toLowerCase());
            }
        });

        this.entityManager.flush();
        this.entityManager.getTransaction().commit();

    }