Given that spawning threads in Java EE containers are discouraged. Would using the Java 8 parallel streams, which may spawn threads, inside Java EE be discouraged too?
EDIT See alternate answer from andrepnh. The below may have been the plan, but it doesn't appear to have played out that way in practice.
The way I read it from the lambda-dev mailing list discussion mentioned in the comments: it's not discouraged the way spawning threads is - but won't do anything much for you in a Java EE context.
From the linked discussion:
the Java EE concurrency folks had been already talked through this, and the current outcome is that FJP will gracefully degrade to single-threaded (even caller-context) execution when running from within the EE container
So you're able to safely use parallel streams in a procedure or library that runs in both contexts. When it's run in a SE environment, it will make with the magical parallel shenanigans - but when it's run in an EE environment it will gracefully degrade to serial execution.
Note: the phrase quoted above is future tense - does anyone have a citation for some definitive documentation?