Android APK, also referred to as application package files, are identified with the extension ".apk". This is also the extension of JAR. If you have a gadget that runs on Android system, you will find out that there are already APK in it which means that you can install and distribute apps made for Android system.
It is important for you to know the basics about these files. Actually, most of the Android users are not fully aware of the importance and implication of APK files. While it is true that sometimes you can live with not fiddling much about APK files, it would still be quite useful to learn about it just in case you would need it in the future when you want to download more apps for your Android device.
Important Information About These Files
APK files are already included in the applications that you get from the Android Market App Store. Usually, your Android device will automatically install the APK. However, if the application that you have is not from the Android Market, you need to make sure that you install it manually in your device. This step is needed so that your apps will run successfully without any hitch.
How are APK files installed?
Normally, APK files are installed automatically especially if the apps are from the Android market. Otherwise, you just need to save or copy the file in your Android gadget's memory. Once you have finished installing, you have to make sure that you manually update the file by exporting the new file, and copy to the Android device's memory again.
Where can free APK files be found?
You can use a highly reliable search engine such as Google so that you can search for free files of games, apps, and widgets for all your gadgets that run on Android system. Use "inurl:htm -inurl:html intitle:"index of" apk", "inurl:htm -inurl:html intitle:"index of" apk games", or inurl:htm -inurl:html intitle:"index of" apk angry birds". You can also key in "site:xda-developers.com apk download". Of course, you can also try the Android Market, and other websites that specialize in promoting Android based applications. Always remember that there are certain rules and regulations that govern apps prior to approval and release in the market. There are certain criteria and requirements that developers need to satisfy. Note that third party apps may still ask for manual installation of APK files.