Theose settings are specific to running code in what the
EJB specificaiton calls "unspecified context." This is what happens when using code in the web container or in EJB methods specificed as Bean Managed TRANSACTIONS, Never, NotSupported, or Supported when the caller is non transactional. It also specific when you allow demaraction of transactions by using auto-commit option directly in
JDBC (or JMS session). If you use UserTransaction or Container Managed Transactions (Requires or RequiresNew), these local Tx setting are irelevant. You should rely on the WAS Gloabl transaciton manager. if you are concerned about performence. WAS will only do a 1pc for transacitons that use one resource.