Sun retained restrictions on mobile Java though and it wasn't opened royalty free. That's the whole story with Oracle attacking Google later (on patent basis). And don't forget, MS sided with Oracle there, claiming that APIs should be copyrightable.
So while this development is positive, one should take it with a grain of salt. MS still can't be just trusted blindly.
That's good. But that's just the compiler. What about APIs (i.e. .NET)? I don't think Oracle claimed ownership over Java compilers in the example above. It was primarily about Java APIs.
One version of the core libraries (micro framework) are OSS too, along with a bunch of other stuff, but by no means everything or even everything in the base class library.
From that perspective yes. But MS clearly showed they didn't like that. It was about the attitude in general. If MS want to really open things up, they should formally have an open license for APIs that would protect them from MS patent and copyright threats.
I really hope that the ruling by judge Alsup stands, but Microsoft and Oracle is currently trying to overturn that ruling and make API's copyrightable.
Sun open sourcing Java SE was the best thing that happened to the software industry in the last 10 years, at least. I don't care about Sun's motivation for doing it, but OpenJDK is here to say and Oracle cannot take that back, even if they wanted to. That's the power of open-source released under a strong license and the JVM is in fact turning into the new POSIX.
Here's to hoping that Microsoft goes beyond the compiler and open-sources the VM and the whole standard library too - .NET and C# always had great potential, it's a pity that Microsoft saw it as a way to sell Windows. And I hope they realize they have a long way to go before they catch up.
Makes me think of Sun open sourcing Java.