Android is an operating system developed by Google. It is modified version of Linux kernel and other open source software. Today android used in many electronic devices like touchscreen mobile, tablets, android TV, Android Auto for cars, and Android watches, each with a specialized user interface. Android are also used on game, digital cameras other electronics.
Android Application Fundamental:
An archive file with .apk extension, an Android package. One APK file contains all the contents of an Android app and is the file that Android-powered devices use to install the app. Android SDK tools compile your application code along with data and resource files into an APK.