InputStream class is an abstract base class which do provides the minimal programming
interface and partial implementation of the input streams in Java. The InputStream
defines the methods to read bytes or the arrays of bytes, marking the locations in stream,
skipping the bytes of input, finding out the number of bytes which are available for
reading, and resetting current position within the stream. The input stream is
automatically opened when we create it. we can explicitly close the stream with the
method close(), or let it be closed implicitly when a object is garbage collected.