The new Dalvik JIT compiler
Google比了很多隻手機，整理出對於CPU-bound code，Android 2.2跟Android 2.1比起來快了2-5X倍。
New enterprise capabilities
關於EAS ( Exchange ActiveSync, an XML based protocol designed for the synchronization of email, contacts, calendar, and tasks from a messaging server to a mobile device ) 的一些新功能。增加對Microsoft Exchange的支援（安全政策, auto-discovery, GAL look-up）
We’ve added Exchange capabilities such as account auto-discovery and calendar sync.
Device policy management APIs allow developers to write applications that can control security features of the device such as the remote wipe, minimum password, lockscreen timeout etc.
Faster, more powerful browser
Rich set of new APIs and services
New data backup APIs enable apps to participate in data backup and restore, allowing an application's last data to be restored when installed on a new or a reset device. Apps can utilize Android Cloud to Device Messaging to enable mobile alert, send to phone, and two-way push sync functionality.
Developers can now declare whether their app should be installed on internal memory or an SD card. They can also let the system automatically determine the install location. On the native side, a new API now gives access to Skia bitmaps.
有關API的修改，可以看回這一篇：Hi Froyo, Android 2.2 announced !
Additions to Android Market
Android Market provides Android Application Error Reports, a new bug reporting feature, giving developers access to crash and freeze reports from users. Developers will be able to access these reports via their account on the Android Market publisher website.
可以收到error report還蠻不賴的。丟出來讓使用者幫忙Field try :Q
a lot of work to do !
其他Google I/O 文章：