Receiving multiple primary key constraint violation exceptions when using SequenceStyleGenerator with optimizer parameter set to pooled-lo. Looking into the source code I found that the generate mathod for the new PooledLoOptimizer is not synchronized. After switching to PooledOptimizer (which has synchronized generate method) every thing works fine.
Hibernate 3.5.6-Final, Oracle 11g, WebSphere 6.1 cluster
Duplicate of HHH-5929.