This seems to be a regression as the issue was fixed in EAP 6.4.5 ref HHH-5255

Writing to a lazy loaded lob property of an entity leads to a ClassCastException during transaction commit when the lob property has not been accessed / lazily loaded before writing to it. The entity is annotated as follows

@Basic(fetch=FetchType.LAZY)
@LazyGroup("smallBlob")
@LazyToOne(LazyToOneOption.NO_PROXY)
Raw

• * Resulting exception
  Raw
  java.lang.ClassCastException: org.hibernate.bytecode.enhance.spi.LazyPropertyInitializer$1 cannot be cast to java.sql.Blob
  at org.hibernate.type.descriptor.java.BlobTypeDescriptor.areEqual(BlobTypeDescriptor.java:33)
  at org.hibernate.type.AbstractStandardBasicType.isEqual(AbstractStandardBasicType.java:180)
  at org.hibernate.type.AbstractStandardBasicType.isSame(AbstractStandardBasicType.java:170)
  at org.hibernate.type.AbstractStandardBasicType.isDirty(AbstractStandardBasicType.java:206)
  at org.hibernate.type.AbstractStandardBasicType.isDirty(AbstractStandardBasicType.java:202)
  at org.hibernate.type.TypeHelper.findDirty(TypeHelper.java:322)
  at org.hibernate.persister.entity.AbstractEntityPersister.findDirty(AbstractEntityPersister.java:4218)
  at org.hibernate.event.internal.DefaultFlushEntityEventListener.dirtyCheck(DefaultFlushEntityEventListener.java:528)
  at org.hibernate.event.internal.DefaultFlushEntityEventListener.isUpdateNecessary(DefaultFlushEntityEventListener.java:215)
  at org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:142)
  at org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:216)
  at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:85)
  at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:38)
  at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1295)
  at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:468)
  at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3159)
  at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2352)