Android application package file (APK) is the package file used to install applications like software and middleware onto devices with Android operating system and other certain operating systems, such as Blackberry 10 with OS version 10.2.1.
APK files are analogous to other application packages such as MSI packages in Windows or Deb packages in Debian-based operating systems like Ubuntu. To make an APK file, a program for Android is compiled at first, and then all parts are packaged into one file. An APK file contains all information of the program, including code (such as .dex files), resources, assets, certificates, and manifest file. Like many files in other formats, APK files also are able to change names as compilers' need and the file name ends with ".apk".
APK files are a type of archive with .apk as the filename extension, especially in zip packages based on the JAR file format. The MIME type associated with APK files is application/vnd.android.package-archive.