how does java inputstream work , i'm confused

Answer 1

http://tutorials.jenkov.com/java-io/inputstream.html

Answer 2

All I can recall now is FileInputStream, FileOututStream and FileReader and FileWriter which uses read() and write() methods to read from and write to a file and does that taking 1 byte at a time. These come under Byte Streams.

There are a lot of others as well to suit different requirements.