Ever since Oracle announced its intentions of getting its hands on Sun there has been various lingering questions. What happens to the Microsoft-Sun cross patent license agreement that was put in place a few years ago?
When Microsoft and Sun signed that agreement, the companies agreed to share their patent portfolio and they gave each other pats in the back.
What has never been clear is what happened to Microsoft's patents on .NET when Sun open sourced Java under the GPL? Has Sun actually transferred Microsoft's patents on .NET to the public by releasing it under the GPL?
This is the timeline:
Microsoft and Sun Sign 10 year Patent License Agreement: They say nice things in the press and promise to use each other patents.
Sun extends Java with Microsoft patents: C# has a feature called Extensible Metadata, the guys at Sun copied this idea, renamed it and put it in Java. There are likely more, but I am too lazy to look them up.
Sun open sources Java under the GPL Although the GPL requires that people redistributing code transfer the patents they have, this does not apply to Sun which probably did not have the rights to do so. Sun is not going to sue itself, so there would be no reason for distributing software with half the patents they had.
Oracle Buys Sun: and as far as we know, there is no Oracle/Microsoft agreement. The Sun/Microsoft agreement will remain in place, the Sun group would get access to Microsoft technologies and patents, and Microsoft only gets access to Sun patents, not Oracle.
The Question Remains Did Microsoft accidentally let go of all of their .NET patents?