java.lang.ClassCastException: atg.adapter.gsa.GSAItemDescriptor cannot be cast to atg.adapter.gsa.GSAItemDescriptor

ERROR [stderr] (Thread-260) Exception in thread "Thread-260" java.lang.ClassCastException: atg.adapter.gsa.GSAItemDescriptor cannot be cast to atg.adapter.gsa.GSAItemDescriptor
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.custom.AncestorGeneratorService$GSATableAndColumnNames.<init>(AncestorGeneratorService.java:3609)
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.custom.AncestorGeneratorService.updateCatalog(AncestorGeneratorService.java:1638)
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.custom.TreeWalkUpdateService.performService(TreeWalkUpdateService.java:421)
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.CMSService.doService(CMSService.java:214)
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.StandardCatalogMaintenance.performService(StandardCatalogMaintenance.java:546)
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.CMSService.doServiceWithLock(CMSService.java:256)
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.CMSService.doService(CMSService.java:201)
13:12:31,795 ERROR [stderr] (Thread-260)        at atg.commerce.catalog.custom.RunCustomServiceFormHandler$MaintenanceRunner.run(RunCustomServiceFormHandler.java:301)

We were migrating from oracle commerce 10.1.2 to 11.2p2. One of the patches were causing the conflicts.

1. Check if youre using  p16545044_1012_v5_lib.jar. comment out the this patch from the runAssembler call.