Files are the most important mechanism for storing data permanently on mass-storage devices. Permanently means that the data is not lost when the machine is switched off. Files can contain:
Each file is characterized by a name and a directory in which the file is placed (one may consider the whole path that allows one to find the file on the hard-disk as part of the name of the file).
The most important operations on files are: creation, reading from, writing to, renaming, deleting. All these operations can be performed through the operating system (or other application programs), or through suitable operations in a Java program.