Yes. For example, a text editor typically does output to both the monitor and to a disk file. Its input comes from both a disk file and the keyboard.
A processing stream operates on the data supplied by another stream. Often a processing stream acts as a buffer for the data coming from another stream. A buffer is a block of main memory used as a work area. For example, disk file data usually is delivered by the operating system in blocks of 512 bytes at a time. Usually this data is buffered and delivered to a program in more suitable sizes.
You have seen this before.
In the following,
the keyboard sends data to the
System.in which is connected to a
which is connected to a BufferedReader stream.
System.in is a stream object that the Java system
automatically creates when your program starts running.
BufferedReader stdin = new BufferedReader( new InputStreamReader( System.in ) );
The data is transformed along the way.
The raw bytes from the keyboard are grouped
together into a String object that the program
This may seem like an unnecessary complication.
java.io gives you a collection of
parts that can be assembled to do nearly any IO task