Apache POI OpenXML Java API
Enables Java developers to use Office Open XML documents in Java applications (web, line of business, etc)
Apache Stonehenge
Demonstrates practical SOA interoperability across platforms (.NET, PHP, Java) with Apache open source projects using Web Services standards
AppFabric SDK for Java
A open source project that gives Java developers a speed dial to leverage Windows Azure AppFabric Service Bus and Access control
Eclipse Tools for Silverlight
Enables Eclipse developers to build Silverlight applications on Windows and Mac OS
Information Cards for Java
Enables Java developers to support information cards for their web sites using standards WS-* protocols
Restlet Extension for WCF Data Services
Enables Java developers to interoperate with .NET through REST.
Windows Azure SDK for Java
Provides tools and resources to help bridge Java developers to Windows Azure.