is EntityManger thread safe

[ballen]

can EntityManger be used safely via a Singleton pattern ?

EntityManger has been @Inject'd into a SLSB, then put into a wrapper class providing access to the world via Singleton pattern.

is this approach likely to blow up and bite us in the ass?

regards/b

[bill.burke]

This could work, but it is not a pattern we will support, meaning, if it doesn't work in the future we won't fix it.

The next release of the EJB specification will have additional APIs for obtaining EntityManagers. We should have a release by end of June.

[epbernard]

em are not supposed to be threadsafe, you'll need to protect it your self.
Anyway try to avoid what you've described.