Input Output : Introduction « File « Java Tutorial

There are four types of streams: InputStream, OutputStream, Reader, and Writer.

1. Reader. A stream to read characters.
2. Writer. A stream to write characters.
3. InputStream. A stream to read binary data.
4. OutputStream. A stream to write binary data.

For better performance, use the buffered I/O classes: BufferedInputStream, BufferedOutputStream, BufferedReader, and BufferedWriter.

Reading from and writing to a stream dictate that you do so sequentially. The java.io.RandomAccessFile is for non-sequential operations.

For object serialization and deserialization, you can use the ObjectInputStream and ObjectOutputStream classes.