The high end Java server vendors do not appreciate the importance of the low end of the market. Microsoft had built its empire by launching its attacks on the top end using products it first has sold into the mass volume low end. The jBoss founding developer Marc Fluery sees the same pattern with MS .NET:

On the contrary, I would argue that Open Source and JBoss in particular are already Sun's best defense against Microsoft .NET. Only Open Source has proven uniquely resilient to a Microsoft onslaught. In the same way that Linux has prevented MS NT from dominating the server operating system, JBoss will prevent .NET from making serious inroads into the application server tier, the crucial gateway to enterprise software applications.

The other players in the J2EE market cannot offer Sun much support against .NET. Last time I talked to Scott Dietzen, CTO of proprietary J2EE market leader BEA Systems, he claimed that they don't see .NET in the marketplace. Not surprising that .NET lacks visibility in the very pricey end of the enterprise market. At JBoss, we see it plenty. Not only do we see .NET coming into the market, we are good at defending the J2EE turf against it.