class Count {
    public static void main(String args[])
        throws java.io.IOException
    {
        int count = 0;
        while (System.in.read() != -1)
            count++;
        System.out.println("Input has " + count + " chars.");
    }
}    
You've already seen the System class being used to
read characters from the standard input stream.
The character-counting program also uses the
System class to display its output.
System.out.println() displays
its string argument followed by a newline.
println() has a companion method
print() that displays its argument
with no trailing newline.
To explicitly specify the newline character use \n.
System.out implements the standard output stream.
The standard output stream is a C library concept
that has been assimilated into the Java language. Simply put, a stream is
a flowing buffer of characters; the standard output stream
is a stream that writes its contents to the display.
The standard output stream is a convenient place
for an old-fashioned text-based application to display
its output.
See Also
 java.lang.System
java.lang.System
 The Standard I/O Streams from Using System Resources
The Standard I/O Streams from Using System Resources