Android is free open source mobile operating system developed by Google.Inc based on the  Linux kernel based operating system. Android is the highly used operating system for the touch screen mobile devices such as Smartphones, phablets and tablets .The one thing that makes the android different from others is its touch gestures and actions  which are very close to the real world scenarios like pinch to zoom, tap to select, swipe to scroll and many more.

Android source code is released by Google.Inc with open source licenses. Many of the leading mobile industries combines the Original source code with their modifications and release their  specific android versions with respect to the released source code version.