Comparision of transactional map wrappers
> | TransactionalMapWrapper | OptimisticMapWrapper | PessimisticMapWrapper
> Lost update | Possible | Not possible | Not possible
> Dirty write | Not possible | Not possible | Not possible
> Dirty read | Not possible | Not possible | Not possible
> Lost update | Possible | Not possible | Not possible
> Nonrepeatable read | Possible | Not possible | Not possible
> Phantoms | Possible | Not possible | Not possible
> Read Skew | Possible | Not possible | Not possible
> Write Skew | Possible | Possible | Not possible
> Readers block writers | No | No | Yes
> Writers block readers | No | No | Yes
> Writers block writers | No | No | Yes
> Might deadlock | No | No | Yes
> Commit might fail | No | Yes | No
> Isolation Level | Read Committed (with lost updates possible) | Snapshot (Oracle would call it Serializable) | Serializable