APK stands for Android Application package, this is a file format which is used to distribute and install android applications on Google’s Android operating system. This is similar to executable (.exe) files on Windows; the applications which Android users download from online or via Playstore are of .apk format. These files can be an application, software, player, games or upgrades. Nowadays, these files are in high demand
APK files are ZIP formatted which is based on JAR file format; these files are open source and user can create these package files. These application packages can be developed in Java programming language using Android Software Development Kit (SDK). Generally an APK package contains .dex, resources, certificates, lib, manifest and asset program files. The programs developed, are first compiled and the parts are packed into one file (APK) which is ready for installation. The installed Android package files are stored under /data/app folder on your Android phones which is accessible only to its root users.
Some of the most popular APK files are Seesmic, National Rail Enquiries, Skype, Facebook, Google Sky Map, Winamp, Angry Birds, Google Maps Navigation, Need for Speed Free!, Modern Combat 4 Zero Hour, Grand Theft Auto 3, Flickr, 9 Heros Defense, Fluid football and many others
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