spring start parallel transactions in integration test

Question

I've been looking around for a solution but can't seem to find a good one. I have a complex scenario in which I would like to evaluate the behavior of hibernate optimistic locking vs pessimistic locking

The perfect place to do this would be in a good set of integration tests, but I can't seem to be able find a clean way of starting parallel transactions.

• How can I create 2 parallel transactions in a spring integration test without manually creating Threads and injecting SessionFactory objects.

Note that I haven't found a way to create 2 parallel transactions without spawning at least 2 threads (maybe there is a way, I hope you can show me an example of that).

Answer 1

Adding this as an answer as there's not enough space on the comments:

In the past, I've tested on vanilla Spring by creating different EntityManager/Session and later injecting those. I'm not sure how you can do this from an Spring integration test, but it might spark an idea.

In the following code, Account is a tiny object which is versioned. You can achieve the same, if the Spring Integration flow (or whatever is called) can be instantiated with a custom entity manager.

public void shouldThrowOptimisticLockException() {
      EntityManager em1 = emf().createEntityManager();
      EntityManager em2 = emf().createEntityManager();
      EntityTransaction tx1 = em1.getTransaction();
      tx1.begin();

      Account account = new Account();
      account.setName("Jack");
      account.updateAudit("Tim");

      em1.persist(account);
      tx1.commit();


      tx1.begin();
      Account account1 = em1.find(Account.class, 1L);
      account1.setName("Peter");

      EntityTransaction tx2 = em2.getTransaction();
      tx2.begin();
      Account account2 = em2.find(Account.class, 1L);
      account2.setName("Clark");

      tx2.commit();
      em2.close();

      tx1.commit(); //exception is thrown here
      em1.close();
}