Difference in Input/output streams class hierarchy

Diff b/w Input/output streams class hierarchy and Read/Write class hierarchy?

The Reader/Writer class hierarchy is character-oriented, and the InputStream/OutputStream class hierarchy is byte-oriented.

Basically there are 2 types of streams. Byte streams that are used to handle stream of bytes and character streams for handling streams of characters. In byte streams input/output streams are the abstract classes at the top of hierarchy, while writer/reader is abstract classes at the top of character streams hierarchy.