Android is a Linux-based operating system for mobile devices such as smart phones and tablet computers. It is developed by the Open Handset Alliance, led by Google. Android has a large community of developers writing applications that extend the functionality of the devices.
Developers write primarily in a customized version of Java. Apps can be downloaded from third-party sites or through online stores such as Google Play (formerly Android Market), the app store run by Google. In 2014,, there were more than 1,300,000 apps available for Android, and the estimated number of applications downloaded from Google Play was 20 billion.