Web Services Interoperability Technology (WSIT) is an open-source project started by Sun Microsystems to develop the next-generation of Web service technologies.
It provides interoperability between Java Web Services and Microsoft's Windows Communication Foundation (WCF).
[1] It consists of Java programming language APIs that enable advanced WS-* features to be used in a way that is compatible with Microsoft's Windows Communication Foundation as used by .NET.
The interoperability between different products is accomplished by implementing a number of Web Services specifications, like JAX-WS that provides interoperability between Java Web Services and Microsoft Windows Communication Foundation.
WSIT is a series of extensions to the basic SOAP protocol, and so uses JAX-WS and JAXB.