Sun and Microsoft start to dance

"In a very pragmatic present day, we are working with them to make sure we have a stack of web services software available that is wholly plug and play compatible with whatever they implement in the Windows Communications Foundation (WCF), which is web services," he said. "There will be people that argue about how standards should be implemented so it's a bit of a moving target, because the WCF will evolve over time and Microsoft may only partially feel the need to closely track those movements. I'm not trying to say anything negative about Microsoft, and they can't change the WCF on a dime, and they wouldn't want to, as they will be somewhat constrained with that stack as it goes off in to hundreds of millions of applications. So it will become a de facto standard, though necessarily de jure."

The implication is that it will now be possible for developers from either camp to build applications that run across platforms that are philosophically as well as technically different. Altman noted that in the Java and .NET camps, users have a lot of options on what they do and how they do it, but across platforms they are somewhat limited. There are always some protocol conversion issues to deal with.

"The good thing about the web services stacks is that they allow us to communicate between Java and .NET at arm's length, so no one has to invest a lot of time and effort. But while that provides plug and play interoperability between the two programs, it does not provide plug and play integration. The latter would still mean that the semantics of the data would have to be clear and well understood on both sides, and that is not addressed by WS standards, but rather by content standards."

There is also the need to ensure that the sequence of messages - the choreography - is well understood, though this is different from the WS-Choreography standard. Plug and play compatibility comes with a common understanding of the data and process semantics, along with the WS-IP/WCF compatibility. In practice, there will still be a need for both parties to negotiate.

"It is a necessary first step," Altman said. "And the responsibility for the next step goes beyond Sun and Microsoft. It will be the job of user industry consortia, such as banking and manufacturing groups. Some already have addressed this, but very few of them have good end to end content standards as yet, so there will probably still be a need for some negotiation between Java and .NET applications." ®