DuplicateMappingException: Duplicate collection role mapping

Caused by: org.hibernate.DuplicateMappingException: Duplicate collection role mapping model.ItemSet.images
at org.hibernate.cfg.Configuration$MappingsImpl.addCollection(Configuration.java:3211)
at org.hibernate.cfg.HbmBinder.createClassProperties(HbmBinder.java:2189)
at org.hibernate.cfg.HbmBinder.createClassProperties(HbmBinder.java:2164)
at org.hibernate.cfg.HbmBinder.bindRootPersistentClassCommonValues(HbmBinder.java:412)
at org.hibernate.cfg.HbmBinder.bindRootClass(HbmBinder.java:326)
at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:177)
at org.hibernate.cfg.Configuration$MetadataSourceQueue.processHbmXml(Configuration.java:4006)
... 6 more

Reason:

Mapping is redundant. Remove the duplicate entries.