Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255 . If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

A subclass must provide an implementation of this method.

public int read( 
   byte[] b,
   int off,
   int len
)