Did you check out SpringSource's recent announcement on 'Application Platform' and OSGi compatibility?
If not, you are in for a surprise.
SpringSource's application platform is a new container to host Java applications that is NOT compliant with JEE. And that was the intention.
Check out Rod Johnson's interview on SpringSource application platform. His views about present offering and future platform's interoperability with JEE profiles looks interesting. Certainly, I feel its going to ease out lot of complexities in JEE application development right now.
And, in light of this development, I would be interested to know the future roadmaps of IBM Websphere application server and other vendors app servers. Will they follow the path of SpringSource?. Or will they collaborate?
The good news - The enterprise java development and deployment will be easier. Especially, for SOA development, the platform promises to ease out lots of versioning related issues.
Bad news - the enterprise JEE world is further fragmented.