Java IO Streams allow data to flow between programs and devices. The java.io package provides classes for input and output streams that handle data in both binary and character formats. InputStream and OutputStream are abstract classes for reading from and writing to streams in binary. Reader and Writer are abstract classes for reading from and writing to streams in character format. BufferedReader is a concrete class that provides efficient reading of character streams using a buffer. File represents files and supports operations like reading, writing, checking attributes. FileInputStream and FileOutputStream allow reading from and writing to files as binary streams.