session.merge(persistentEntity) fails on unmodifiable collections ----------------------------------------------------------------- Key: HHH-1914 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1914 Project: Hibernate Core Issue Type: Bug Components: core Reporter: Emmanuel Bernard Priority: Minor Cat cat = new Cat(); cat.setId( new CatPk() ); cat.getId().setName( "titi" ); cat.getId().setThoroughbred( "unknown" ); Set<Woman> women = new HashSet<Woman>(); Woman woman = new Woman(); woman.setId( new WomanPk() ); woman.getId().setFirstName( "Lady" ); woman.getId().setLastName( "McBeth" ); women.add( woman ); cat.setHumanContacts( Collections.unmodifiableSet( women ) ); Set<Cat> cats = new HashSet<Cat>(); cats.add( cat ); woman.setCats( Collections.unmodifiableSet(cats) ); s.persist( cat ); s.persist( woman ); tx.commit(); s.merge( woman ); During merge, the entity is copied into itself (?) defaultmergeeventlistener.entityIsPersistent() => copyValues(persister, entity, entity, source, copyCache); java.lang.UnsupportedOperationException at java.util.Collections$UnmodifiableCollection.clear(Collections.java:1037) at org.hibernate.collection.PersistentSet.clear(PersistentSet.java:247) at org.hibernate.type.CollectionType.replaceElements(CollectionType.java:404) at org.hibernate.type.CollectionType.replace(CollectionType.java:449) at org.hibernate.type.TypeFactory.replace(TypeFactory.java:437) at org.hibernate.event.def.DefaultMergeEventListener.copyValues(DefaultMergeEventListener.java:282) at org.hibernate.event.def.DefaultMergeEventListener.entityIsPersistent(DefaultMergeEventListener.java:132) at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:105) at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:51) at org.hibernate.impl.SessionImpl.fireMerge(SessionImpl.java:677) at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:661) at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:665) at org.hibernate.test.annotations.manytomany.ManyToManyTest.testUnmodifiableCollection(ManyToManyTest.java:102) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at org.hibernate.test.annotations.TestCase.runTest(TestCase.java:67) at com.intellij.rt.execution.junit2.JUnitStarter.main(JUnitStarter.java:32) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:90) What is the reason for that? The spec says that "If X is a managed entity, it is ignored by the merge operation"