Open APK File

What are File Extensions?

Information in computers is stored in files. To differentiate between files which store different types of information file extensions are used. File extensions are short sequences of symbols which specify in what format information is stored inside the file.

With file extension there is no need to look inside the file to find out what kind of information is stored in it. All it needed is to look at file extensions and you will immediately know how to deal with the file. For example if file extension is JPG, PNG, PCX, JPEG, HEIC you will immediately know that you are dealing with an image file and to open such file you need a graphics viewer or editor.

Knowing what is stored inside the file helps not only end user but an operating system too. When user double clicks or taps on a specific file in order to open it operating system will know how to open the file based on its file extension. This saves significant processing time. Without file extension operating system would have to look inside the file and check it against all known data formats to figure out which one was used.

File extensions are also very useful for searching files. If for example you want to find all image files on your computer it is very easy to do so because of the file extension. Computer will just need to search for files with file extensions matching ones used by images. And such search could be performed very quickly because there is no need to open any of the files.

When new application is installed to personal computer it notifies operating system which file extensions it supports. This is needed for computer to know which application to invoke when user clicks on a specific file. If there are multiple applications available computer will provide a choice for a user on which application to use to open the file.

File extensions are typically located at the end of the file name and are separated by (.) dot from a file name. For example in picture1.jpg, jpg is a file extension and picture1.jpg is a full file name.