I've been testing with MVCC in order to reproduce write skew. Testing's been done with JPA/Hibernate in this way: 1.- Two concurrent threads read a field of an entity. 2.- Both of them increment (by one) that field based on the value previously read. Results are as expected. R_R causes a Data Versioning Exception and R_C does not produce any exception. However, and this is my question, results with the two transactions are the same. Entity field is incremented one with R_R since one transaction rollbacks and same result is seen with R_C though without exception. Is the behaviour of R_C correct ? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4223524#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...