Introduction of Managing Input/Output Files in Java
Nearly all programs require the ability to transfer data in and out of memory.
For example, data may be stored on disk or sent over a network.
The package java.io, part of the standard Java class library, provides a large number of classes designed for handling input and output to files, network connections, and other sources. These I/O classes are known as streams, and provide functionality for reading and writing data in various ways.
Java’s input and output classes:
• Input streams-and how to create, use, and detect the end of them-and filtered input streams, which can be nested to great effect.
• Output streams, which are mostly analogous to (but the inverse of) input streams.