Regardless of which camp a developer inhabits, Java or Microsoft's .NET, as applications get bigger and become composites they will increasingly need to link to applications in the other camp.

So the introduction of Tango, announced by Sun at the JavaOne conference in San Francisco, comes at a time some form of 'glue' between the two environments is required.

Tango is the project title for Sun's open source implementation of next generation Web Services Interoperability Technology (WSIT), which is designed to provide far greater levels of interoperability between applications or components assembled into composite services. The need for interoperability at some level is now the nature of most business environments.

According to Ross Altman, Sun's CTO of Business Integration and ex-top gun at Sun acquisition SeeBeyond, Tango will play an increasingly important role in the apps development world. "It is the first opportunity to bring the parallel universes of Java and .NET together," he said. "I think it is a red letter day. It is not news that Sun and Microsoft are getting along now, but this is the most tangible evidence of that rapprochement."

His says the industry is still struggling with web service standards, as standards are thoroughly mature and have stopped moving. So with web services, it is still not going to be possible to go out on to the net spontaneously and connect with run-the-business implementations.

"You can negotiate implementations that run business quality, but not on a plug and play basis. Standards have to be unambiguous and broadly adopted, of which WS-I basic profile is a good example."

In fact, the kick-off point for Tango has been Microsoft, which came out with the Windows Communications Foundation. "This was the start of it," he said, "and from Vista going forwards there will be a reference implementation of web services standards. It will be subject to Microsoft's interpretation and we have to accept that. We may not like it but that is the way it will be. As a vendor, and politically, I wish it wasn't that way, but as a practical matter it is what it is."

The sense of realism Altman shows will probably be welcomed by a good many enterprise users of Java and .NET, though it obviously lacks the humour that used to underpin the long history of sniping between the two companies.