There is very little information yet for mobile developer about the Android SDK . I see 3 possible options:
Option 1) it comes with a native open source JVM. This is the Blackberry approach and the best scenario. It will enable running existing J2ME applications (thousands exist today) and Google will provide more powerfull APIs for their integrationg with their application suite, like GMail, Google Maps and YouTube. GPS APIs would be great too. They will also provide a custom Java based UI toolkit to make applications consistent with the phone UI. IDEs will be Netbeans and Eclipse. The low level access to the underlying Linux OS would be hidden from the developer.
Option 2) The JVM is not part of Android, but available as a addon. This is Palm approach (IBM provides the JVM for Treos). In this case, Esmertec will likely provide a non open source JVM to run J2ME apps to each phone vendor. This is OK but not very good, as the JVM may or may not be present and they will be no integration with existing app or UI toolkit. Developer will have to code all apps running on Android with C or C++ APIs using Eclipse. the SDK will be very similar to the now defund Palm Foleo or the Nokia Linux Maemo platform.
Option 3) No JVM, but a powerfull mobile Web Browser ala Safari, based on the Safari WebKit, which is open source, to runn local mobile AJAX apps written in Javascript and DHTML. Google would provide in the browser custom APIs as Javascript libraries to integrate with the platform and custon Javacript UI compomenents. This will be similar to the current iPhone development and also like the Google widget developement. This is ambitious and risky and will not work for mutimedia or game apps. This is not GREAT, but this is OK, specially if they can integrate some version of Google Gears, enabling mobile AJAX apps to run offline.
OR ... all 3 options ? Anyway we will know in 1 week time.
Thierry BRETHES
http://www.unyverse.com