An OutputStream handles byte data.
OutputStream is an abstract class from which all
byte-oriented output streams are derived.
Its descendant classes are used for general-purpose
(non-character output).
These streams are aimed at
writing groups of 8-bit bytes to output destinations.
The bytes are in the same format as Java primitive types.
For example,
4-byte groups corresponding to type int can
be written to a disk file.
We will mostly be interested in FileOutputStream
and DataOutputStream.
We have used PrintStream many times already,
because System.out is an object of that type.
Say that you wrote 32-bit int data to a disk
file using DataOutputStream.
What input stream class would another program use
to read that file?