Question

I’ve just started using hibernate 3.6.0 and JPA 2.0 and I’m having some troubles.

I get InvalidClassException on some queries. By the way I’m using metamodel with hibernate-jpamodelgen.

I.e. one below runs fine:

CriteriaBuilder cb = getCriteriaBuilder();
CriteriaQuery<UserEntity> cq = getCriteriaQuery(cb);
cq.where(cb.equal(cq.from(UserEntity.class).get(UserEntity_.username), username));

but with this one I’m having trouble:

CriteriaBuilder cb = getCriteriaBuilder();
CriteriaQuery<UserGroup> cq = getCriteriaQuery(cb);

cq.where(cb.equal(cq.from(UserGroup.class).join(UserGroup_.entries).join(UserGroupEntry_.user).get(UserEntity_.id), user.getId()));

I get exception like below.
All classes used in query implements Serializable.

I’m kinda lost here so any help would be appreciated.

java.io.InvalidClassException: com.ptm.model.BaseEntity; local class incompatible: stream classdesc serialVersionUID = 7662749495871325837, local class serialVersionUID = 8176072949097236524
     at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:579)
     at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1600)
     at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1513)
     at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1600)
     at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1513)
     at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1749)
     at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1346)
     at java.io.ObjectInputStream.readObject(ObjectInputStream.java:368)
     at org.hibernate.util.SerializationHelper.doDeserialize(SerializationHelper.java:244)
     at org.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:306)
     at org.hibernate.type.descriptor.java.SerializableTypeDescriptor.fromBytes(SerializableTypeDescriptor.java:130)
     at org.hibernate.type.descriptor.java.SerializableTypeDescriptor.wrap(SerializableTypeDescriptor.java:116)
     at org.hibernate.type.descriptor.java.SerializableTypeDescriptor.wrap(SerializableTypeDescriptor.java:39)
     at org.hibernate.type.descriptor.sql.VarbinaryTypeDescriptor$2.doExtract(VarbinaryTypeDescriptor.java:62)
     at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:64)
     at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:253)
     at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:249)

Answer 1

This exception says that an object of class BaseEntity was stored in the database in serialized form and can’t be deserialized because the class have been changed.

Storing objects in serialized form is a fallback strategy used by Hibernate when it can’t figure out how object should be stored (i.e. it’s not configured). Usually it’s not a desired behaviour.

Perhaps in your case it means that one of the relationships between entities (UserGroup_.entries or UserGroupEntry_.user) is improperly configured.