The default OptimisticCallback plug-in is used by the run time if an implementation is not provided by the application. If a well-constructed equals(Object) method is not on your value object, this exception occurs because the entire value object is used as the version object.
Because this exception indicates that the map entry contains stale data, stale map entries or entries as identified by the key parameter that is passed to the OptimisticCollisionException(String, String, String, Object) method are invalidated. If this exception is thrown by a Loader plug-in and a null reference is used as the key parameter by the loader, the run time assumes that the loader does not know which entry caused the exception. In this scenario, the LogSequence object is passed to the Loader.batchUpdate(TxID, LogSequence) method to determine which map entries to invalidate. Each LogElement entry in the LogSequence object that is type update or delete is invalidated.
System Exception
IBM.WebSphere.Caching GridException
IBM.WebSphere.Caching.Map OptimisticCollisionException
Namespace: IBM.WebSphere.Caching.Map
Assembly: Client.Api (in Client.Api.dll) Version: 8.6.0.0