InputStream is an abstract class from which all byte-oriented input streams are derived. Its descendant classes are used for general-purpose input (non-character input). These streams deliver data to a program in groups of 8-bit bytes. The bytes can be grouped into the size necessary for the type of data.

For example, if a disk file contains 32-bit int data, data can be delivered to the program in 4-byte groups in the same format as Java primitive type int.

We will be mostly concerned with DataInputStream and FileInputStream.