The Byte stream classes

Byte streams are defined by using two hierarchies. The entire top is two abstract classes, Input stream and output stream. Each of these abstract classes has several concrete subclasses that handle the differences between various devices such as disk files, network connections and every memory buffers. The abstract classes input stream and output stream define several methods that the other stream classes implement. Both methods read and write bytes of data are declared as abstract inside input stream and output stream.