I belive the reason for this has to do with the license IBM has with Sun. IBM’s VM used to be able to be used on any computer, up to and including 1.3.x. However, in 1.4.x and newer, the restriction was put in.

You’ll notice that it’s the same code that they use for the VM when bundled with Eclipse (which is freely distributed), or any of their Java-based products such as Websphere (which are not). Those VM’s do not have the limitation of running only on IBM hardware. In fact, before IBM released the 1.4.0 JDK, the usual way of getting the code at *all* was to download an obscure fixpak of MQ Series and pull it from there. That might still be possible. Of course, I run IBM hardware, so I can just download the normal one….

On the other hand, the last time I did programming, I remember that IBM’s was the fastest JRE. Maybe they’re trying to bundle that performance with their hardware, so people are more likely to buy their hardware, to get access to that extra performance, but it’s a long shot.

The most important issue I can think of is that people won’t be able to develop on other hardware and then deploy on IBM, using the same JRE. This would mean that people can either do another bunch of testing on the actual machine, give up on IBM servers or buy IBM workstations. Not good.