Gooossshhh, I'm sorry Manik. I decided to test it all again and pay better attention to the traces. EVERYTHING is working fine, I mean, R_R semantic DO BLOCK writing if a reader already holds the lock. R_C allows writers to proceed, EXACTLY as described in hibernate guide. Thanks for your support that took me to a better knowledge of the cache. BTW, don't take this error into account and please keep on answering my future questions ;-) Thanks again. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4223436#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...