Android™ How to Program, Second Edition

Files as Streams of Bytes

Java views each file as a sequential stream of bytes (Fig. J.10). Every operating system provides a mechanism to determine the end of a file, such as an end-of-file marker or a count of the total bytes in the file that’s recorded in a system-maintained administrative data structure. A Java program processing a stream of bytes simply receives an indication from the operating system when it reaches the end of the stream—the program does not need to know how the underlying platform represents files or streams. In some cases, the end-of- file indication occurs as an exception. In other cases, the indication is a return value from a method invoked on a stream-processing object.

Fig. J.10 | Java’s view of a file of n bytes. ...