This should be a good thing for companies investing in either technology and it bodes well for the general state of partnership and collaboration between the main players in the standards and protocols being developed for web services, though a positive result here is less certain.
Sun should count itself fortunate that J2EE is still a leading player in web services, thanks in no small measure to the efforts of IBM and BEA. How these two will respond to the freshly-baked warmth in the Sun/Microsoft relationship will be of critical interest to J2EE's customers.
The question customers of both firms will have is how long it will be before this co-operation results in products and technologies they can deploy.
A possibility is that although the agreement is very new, the discussions have been going on for more than a year and some preliminary collaboration work may have happened which could produce a relatively quick result. But even if there were no "quick-win" products, web services standards are here for the long term and we should see the fruits of this collaboration before too long.
The caveat, of course, is that Sun's weakness in the marketplace could have a negative impact on J2EE's momentum. We need a strong J2EE in the market - Sun and its partners will need to figure out a co-operative path to countervail the progress of .net.
Regrettably, the co-operation announcement may be the end of Scott McNealy's verbal riffing with Bill Gates which produced classics about .not, Gates as Darth Vader and Microsoft as the dark side. To misquote CS Lewis on Narnia, "The holidays are over, the school term has started, the dream has ended."
Jyoti Banerjee is director of analyst company MyBusiness.Net