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.

OutputStream class is the abstract base class which provides minimal programming interface and the partial implementation of the output stream in Java. the OutputStream defines methods for writing the bytes or arrays of bytes to stream and flushing the stream. The output stream is automatically opened when we create it. We can explicitly close the output stream using close() method, or let it be closed implicitly when an object is garbage collected.

Following is an overview of input and output streams, classes which inherits directly from the InputStream and the OutputStream which are not abstract classes.

The FilterInputStream and FilterOutputStream are subclasses of the InputStream and OutputStream respectively, and both are abstract classes. These classes will define interface for the filtered streams. Filtered streams processes the data as it is being read or written. Consider for example, BufferedInputStream and BufferedOutputStream classes buffer data while reading and writing to speed it up.