"ALRubinger" wrote : | ...if you set stuff in a ThreadLocal, ensure that its removed if the Thread has been obtained from a Thread pool. Otherwise, nightmares. | Thanks ALR, I'll watch out for that "ALRubinger" wrote : | Or in your case...if you don't want to put any JPA stuff in your DAO APIs...why not just pass the EM into the DAOImpl Constructor? | DAOImpls are currently singleton per DAO iface, but must be thread safe, so I'm using ThreadLocal rather than passing in via method parameters. I could stop using a singleton and create a DAOImpl per DAO request (as you suggest), but then I have a proliferation of DAOs just to ensure thread safety which smells of an antipattern. Thank you for your comments everyone. C View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3984828#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...