Categories of file:

• A text file consists of data that can be read in a text editor. Data in a text file is encoded using a scheme. The most common schemes are ASCII and Unicode. Examples are program files and application files.
• A binary file contains data that is not encoded as text. This file has contents in binary format, which means they cannot be understood by viewing them in a text editor. Examples are images, music, and the .class extension files which are created after compiling Java programs.