[jboss-as7-dev] thread safety and AS Service implementations...

I would like to get agreement on whether we still need to protect Service instance variables. From reading the javadoc in the org.jboss.msc.service.Service class, mutable instance variables (in Service implementations) need their own thread safety protection. I had a mutable object reference in class PersistenceUnitService that is set in the Service start method and cleared in stop(). Someone reported a NPE caused by the same mutable object reference, so I think we need to guard against this pattern elsewhere most likely (forum post about NPE http://community.jboss.org/message/621316). https://github.com/scottmarlow/jboss-as/commit/c0f05311680cb936fb1abcb739... changes the variable to be volatile. The down side is that the object reference won't be cached. I don't know for sure, that the above code change will fix the NPE, just seems likely to me. Scott