File Streams

Until now, most of the examples in this book have used the streams System.in and System.out. These are convenient for examples, but in real life, you'll more commonly attach streams to data sources like files and network connections. The java.io.FileInputStream and java.io.FileOutputStream classes, which are concrete subclasses of java.io.InputStream and java.io.OutputStream, provide methods for reading and writing data in files. What they don't provide is file management, like finding out whether a file is readable or writable or moving a file from one directory to another. For that, you may want to flip forward to Chapter 17, which talks about the File class itself and the way Java works with files.