Given
* Batch fetch is enabled
* 2nd Level cache is enabled
* Polymorphic entity annotated with {{org.hibernate.annotations.Cache}}
When
* find entity by id using id from another type
Then
* ClassCastException occurs
{code:java}@Entity
@Table(name = "THE_ENTITY")
@DiscriminatorColumn(name = "DISC_COL", discriminatorType = DiscriminatorType.INTEGER)
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public abstract class AbstractEntity {
@Id
@Column(name = "ID")
Integer id;
}
@Entity
@DiscriminatorValue("1")
public class EntityA extends AbstractEntity {
}
@Entity
@DiscriminatorValue("2")
public class EntityB extends AbstractEntity {
}{code}
{code:java} @Override
protected void configure(Configuration configuration) {
super.configure(configuration);
configuration.setProperty(AvailableSettings.SHOW_SQL, Boolean.TRUE.toString());
configuration.setProperty(AvailableSettings.FORMAT_SQL, Boolean.TRUE.toString());
configuration.setProperty(AvailableSettings.DEFAULT_BATCH_FETCH_SIZE, "10");
configuration.setProperty(AvailableSettings.USE_SECOND_LEVEL_CACHE, Boolean.TRUE.toString());
configuration.setProperty(AvailableSettings.CACHE_REGION_FACTORY, JCacheRegionFactory.class.getName());
configuration.setProperty("hibernate.javax.cache.provider", EhcacheCachingProvider.class.getName());
}
@Test
public void hhhXXXXTest() throws Exception {
Integer id = 123;
try (Session s = openSession()) {
Transaction tx = s.beginTransaction();
EntityA entityA = new EntityA();
entityA.id = id;
s.persist(entityA);
tx.commit();
}
try (Session s = openSession()) {
EntityA entityA = s.find(EntityA.class, id);
assertThat(entityA.id).isEqualTo(id);
}
try (Session s = openSession()) {
EntityB entityB = s.find(EntityB.class, id);
assertThat(entityB).isNull();
}
}{code}
{noformat}java.lang.ClassCastException: class org.hibernate.bugs.EntityA cannot be cast to class org.hibernate.bugs.EntityB (org.hibernate.bugs.EntityA and org.hibernate.bugs.EntityB are in unnamed module of loader 'app')
at org.hibernate.bugs.ORMUnitTestCase.hhhXXXXTest(ORMUnitTestCase.java:81)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
at org.hibernate.testing.junit4.ExtendedFrameworkMethod.invokeExplosively(ExtendedFrameworkMethod.java:45)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:299)
at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:293)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.lang.Thread.run(Thread.java:833){noformat}
Some notes:
* This issue doesn’t happen in latest hibernate 5.6.x
* This also happens with infinispan cache, not only ehcache. So, it doesn’t seem related to the cache engine used.
* Disabling 2nd level cache avoids the issue
* Disabling batch fetch also avoids the issue
Although trying to find EntityB with EntityA id could be considered an application/logic bug by itself, I would expect hibernate to have a consistent behaviour enabling or disabling batch fetch; or enabling or disabling 2nd level cache and do not throw ClassCastException, but rather return null.
Failing test case to be attached and also available at [https://github.com/ratoaq2/HHH-16565|https://github.com/ratoaq2/HHH-16565|smart-link] |
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