Android now uses a just-in-time compiler that improves the performance for some applications, especially for games. "The new Dalvik JIT compiler in Android 2.2 delivers between a 2-5X performance improvement in CPU-bound code vs. Android 2.1 according to various benchmarks," says Xavier Ducrohet.
Android's browser includes the V8 JavaScript engine created for Google Chrome, so web pages that use JavaScript heavily will load much faster (some benchmarks show a 2-3X improvement). Google claims that Android's browser is the fastest mobile browser available today.
Developers have a new API for app data backup, which is really useful if you want to switch to a new Android device or you want to install a custom version of Android. There's also an extremely useful messaging API for sending data to an Android phone from another device. For example, you'll be able to send a link from your computer to your Android phone and the phone will automatically open the browser and navigate to the web address. You can also send files and install applications from your computer over the air.
Android Market will have a web interface, applications can auto-update and you can quickly install all the updates, instead of manually installing each update. Another change is that applications can be moved to the SD card. Google also announced that it has acquired SimplifyMedia, a company that developed some cool applications for streaming your music.
Android 2.2 has built-in support for tethering and it can transform a phone into a portable hotspot. Android Market includes some great applications for tethering, but it's nice to see that's now a built-in feature.
You can add multiple languages to the keyboard and switch between them by swiping across the space bar, there's a new UI for the camera, there's support for Exchange calendars and remote wipe, LED flash for the Camcorder, support for sharing contacts with other phones and much more.
Flash 10.1 is now available as a beta application in the Android Market, but it requires Android 2.2. Nexus One and Motorola Droid will be updated to Froyo next month. The other HTC phones launched this year will be updated in the second half of the year. "This includes popular models like the Desire and Droid Incredible as well as hotly anticipated phones like the Evo 4G, MyTouch slide and upcoming models."