While I agree that a move to 1.5 would be nice you have to consider that not all platforms support 1.5 at the moment. In particular IBM z/OS which is a typical platform that my company tends to deploy into. FreeBSD is only in the beta phase of producing a native 1.5, you can run the Linux version in emulation. Also, most of the application servers out there are still only 1.4, so limiting to 1.5 only works in a "standalone" mode. If there is a way to take advantage of the language constructs in 1.5 but target 1.4 byte code then I would be all for it. Retroweaver is interesting, but does it produce production stable byte code?
Has anyone on here REALLY used it in a production environment?
