Here’s something you probably haven’t even heard of yet. It’s a little something that Google engineers have been working on for over two years, which will change the very way your Android smartphone runs apps.
ART, which is short for Android Runtime, aims to replace Dalvik and change the way your Android-powered smartphone runs. Dalvik is the one responsible for running apps on Android. Its runtime uses the JIT complier (Just-In-Time) to interpret bycode, which is a partial version of the original application code. ART uses the AOT process (Ahead-Of-Time) and basically pre-compiling the bytecode into machine language the moment an app is installed, making them in essence native apps.
For a more detailed explanation visit the source link. Meet ART, Part 1: The New Super-Fast Android Runtime Google Has Been Working On In Secret For Over 2 Years Debuts In KitKat