JPA Entities and the Persistence Context

The code below moves the start of the Evening Concert 30 minutes later. It loads the event, changes one field, and ends. It never calls save, update, or any other write method.

tx.executeWithoutResult(status -> {
    Event evening = em.find(Event.class, eventId);
    evening.setStartsAt(evening.getStartsAt().plusMinutes(30));
    System.out.println("changed startsAt, no save call; leaving transaction");
});
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With SQL logging switched on, the run printed this.

Hibernate: select e1_0.id,e1_0.starts_at,e1_0.title,v1_0.id,v1_0.name,v1_0.rows,v1_0
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