Google's annoucement of the Open Handset Alliance a few days ago wasn't that exciting: an interesting group of partners and some interesting perspectives, but the meat was missing. It arrived yesterday with the actual release of the Android SDK. And... wow!

This is a complete stack, from the kernel (Linux, of course) up to a very capable web browser ( Webkit, also used on the iPhone and the Nokia's) up to the application layers. And the application development is done in Java... or is it?

Google had an incredibly clever idea: Android doesn't run Java, but uses Java bytecodes as an input for a compiler targetting an non-Java virtual machine called Dalvik. Android doesn't claim to be Java compliant (and even less J2ME), and as such doesn't have to pay licence fees to Sun. Moreover, Android ships with a good subset of the J2SE standard library they obtained from Apache Harmony (see also Stefano's post).

So what does all this mean? Google has addressed the mobile market the other way around than Apple: the iPhone is gorgeous hardware with a completely locked system that will eventually allow 3rd party applications in February. Android is a completely open platform, with nice development tools that doesn't yet have any hardware to run on. But we can expect that very quickly, a lot of asian companies which are so good a building hardware but so bad at writing software will embrace Android and provide us with a tsunami of new cool devices, that thousands of Java developers will feed with cool applications.

So with Android, Google is pissing off a lot of people: Apple whose iPhone will stay in a luxury niche, Sun who won't get big bucks from a successful mobile Java-ish platform, and of course Microsoft since we can assume the clunky Windows Mobile will quickly vanish. OpenMoko is also probably stillborn. Now what is Google's intent? Is it just about commoditizing the mobile application market to expand the reach of its advertising platform, particularly with location-based ads? Is it about knowing all about us to increase the targetting and thus the ad selling price?

After OpenSocial, it looks like Google is taking over the platform market. But with open source software, meaning the battle moves to another front, that of our data. This is not less dangerous since data is much more valuable than dumb software. But at least we can hope independent storage services will exist for the privacy-conscious among us.