I believe that JRubyOnRails is paving the way for ruby and rails to be integrated into enterprise rather than being the sole domain of cutting edge developers. Perhaps its important that enterprise realises the power of rails or perhaps not (it might be better to keep it for ourselves). Regardless the ability to run ruby on rails applications on Java Application Servers is a big step towards acceptence in the enterprise. For those that aren’t familiar with this ability google ‘warbler’ and run through the tutorial. It is a little more complex to get a larger project to run on a Java Application Server but not so much that would deterr people. It will likely be a long path before its a mainstream technology but it’s a good first step.
It’s also not necessarily a good thing to be tied to java, but when enterprise is so slow to embrace new technologies and better ways of doing things it is important to compensate to some degree. Not making them completely replace the Java application server that they paid to much for in the first place may make that admission and acceptence a little easier.
UPDATE: I’ve since started following @headius on twitter, the primary force behind JRuby. He is outstanding, and his belief in getting ruby accepted in the enterprise is inspirational.