The Android is a software stack for mobile apparatus by means of the intention of contains an operating system, middleware and key submission. The Android SDK make available the tools and APIs necessary to begin developing submission on the Android platform utilizing the Java programming language. Android has a outsized community of developers writing submission programs ("apps") by means of the intention of extend the functionality of the piece of equipment. There are presently in excess of 100,000 apps obtainable for Android. Android Market is the online app store run by Google, even though apps be able to be downloaded commencing from third party sites (excluding on AT&T, which disallows this).