A transactional cache in Infinispan supports two different transactional models, optimistic and pessimistic.
The optimistic model refers to an approach in which transactions are allowed to proceed, with conflicts resolved as late as possible, deferring lock acquisitions for the transaction, in order to prepare time.. The entry will not be immediately locked when it is accessed by a transaction, which means that the cache entries will be available to other transactions for concurrent access, opening up the possibility of conflicts.
At commit time, when the entry is about to be updated in the grid, Infinispan will compare the version of the current object to the version that was initially saved at the moment the entry was first requested in the transaction. If both versions differ from each other, Infinispan will consider that a conflict exists, and will mark the transaction for rollback. This avoids deadlocks, optimizes the lock acquisition time, and increases throughput...
