Code review comment: Remember it's a nested nodes structure, so you could still use the `hibernate.` prefix, as long as we manage to disambiguate sub elements.  Specifically, `hibernate.query.executions` is taken, but you could use `hibernate.fulltextquery.executions`, or `hibernate.search.fulltextquery.executions`.  And yes it's annoying, but I also give up.. let's consider that this PR is about better integration with an existing library which did behave like this.  If one of you (both) feel very strongly this is wrong, I propose you follow up with a patch which makes the prefix configurable; if we default to `hibernate-orm` there's a (very remote) possibility that you manage to eventually re-educate the rest of the universe, but before we get there consider you'll be annoying many users who will be forced to figure out what's wrong, find the configuration property, reconfigure all their apps.

Code before review:
public void testMetrics() {
assertEquals(0L, getCounterValueOrNull("hibernate.query.executions",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
assertEquals(0L, getCounterValueOrNull("hibernate.entities.inserts",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
assertEquals(0L, getCounterValueOrNull("hibernate.cache.query.requests",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME),
new Tag("result", "miss")));
Arc.container().requestContext().activate();
try {
DummyEntity entity = new DummyEntity();
entity.number = 12345L;
em.persist(entity);
em.flush();
em.createQuery("from DummyEntity e").getResultList();
assertEquals(1L, getCounterValueOrNull("hibernate.query.executions",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
assertEquals(1L, getCounterValueOrNull("hibernate.entities.inserts",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
} finally {
Arc.container().requestContext().terminate();
}
}

Line under review: assertEquals(0L, getCounterValueOrNull("hibernate.query.executions",

Code after addressing the review:
public void testMetrics() {
assertEquals(0L, getCounterValueOrNull("hibernate.query.executions",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
assertEquals(0L, getCounterValueOrNull("hibernate.entities.inserts",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
assertEquals(0L, getCounterValueOrNull("hibernate.cache.query.requests",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME),
new Tag("result", "miss")));
Arc.container().requestContext().activate();
try {
DummyEntity entity = new DummyEntity();
entity.number = 12345L;
em.persist(entity);
em.flush();
em.createQuery("from DummyEntity e").getResultList();
assertEquals(1L, getCounterValueOrNull("hibernate.query.executions",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
assertEquals(1L, getCounterValueOrNull("hibernate.entities.inserts",
new Tag("entityManagerFactory", PersistenceUnitUtil.DEFAULT_PERSISTENCE_UNIT_NAME)));
} finally {
Arc.container().requestContext().terminate();
}
}