Scenario:
- I created an entity manager
- I queried a list of entities
- I called parallelStream on them, and called some getters which resulted in loading additional entities
- I cleaned the entity manager
- I repeated the process, and a NullPointerException was thrown during cleaning
Stacktrace:
{code:java}
java.lang.NullPointerException
at org.hibernate.engine.internal.StatefulPersistenceContext.clear(StatefulPersistenceContext.java:234)
at org.hibernate.internal.SessionImpl.cleanupOnClose(SessionImpl.java:572)
at org.hibernate.internal.AbstractSharedSessionContract.setClosed(AbstractSharedSessionContract.java:315)
at org.hibernate.internal.AbstractSharedSessionContract.close(AbstractSharedSessionContract.java:308)
at org.hibernate.internal.SessionImpl.close(SessionImpl.java:412)
{code}
Test case:
{code:java}
private static EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("JPA_PERSISTENCE_UNIT_NAME");
@Test
public void testHibernate() throws InterruptedException {
run();
run(); //exception thrown only for 2nd run
}
public void run() throws InterruptedException {
EntityManager em = entityManagerFactory.createEntityManager();
try {
List<MyEntity> entities = em.createQuery("from MyEntity").getResultList();
entities.parallelStream()
.forEach((e) -> {
//only happens when loading at least 2 different referenced entities
e.getReferencedEntity().getId();
e.getAnotherReferencedEntity().getId();
});
} finally {
em.close();
}
}
{code}
Where MyEntity looks like:
{code:java}
@Entity
@Table(name = "my_entity")
@Audited
public class MyEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id_a")
@Audited(targetAuditMode=RelationTargetAuditMode.NOT_AUDITED)
private A referencedEntity;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id_b)
@Audited(targetAuditMode=RelationTargetAuditMode.NOT_AUDITED)
private B anotherReferencedEntity;
//Constructor, getters, setters
}
{code}
The exception is thrown at StatefulPersistenceContext.java:234, which is:
{code:java}
for ( Entry<Object, EntityEntry> objectEntityEntryEntry : entityEntryContext.reentrantSafeEntityEntries() ) {
// todo : I dont think this need be reentrant safe
if ( objectEntityEntryEntry.getKey() instanceof PersistentAttributeInterceptable ) { //<-- this line
...
{code}
While debugging I discovered that entityEntryContext.reentrantSafeEntityEntries() returned a collection an array in which some elements were null.
The issue doesn't appear if I replace the parallelStream() with a simple stream(). |
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