This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
the above examle shows how you can set isolation level through EBeans
in ejb3 it is not possible to set isolation level programatically if you are using connection pooling,to set refer your servers Docs
if you are not using connection pooling then you can set isolation levels programatically like this