Understanding Streams - Beginning Java 2 SDK - page 326

The data is read from the stream by these methods simply as bytes. No conversion is applied to the
bytes read. If any conversion is required, for a stream containing bytes in the local character encoding
for instance, you must provide a way to handle this. We will see how this might be done in a moment.

You can skip over bytes in an InputStream by calling its skip() method. You specify the number of
bytes to be skipped as an argument of type long , and the actual number of bytes skipped is returned,
also a value of type long . This method can throw an IOException if an error occurs.

You can close an InputStream by calling its close() method. Once you have closed an input stream,
subsequent attempts to access or read from the stream will cause an IOException to be thrown.

The InputStream class has seven direct subclasses as shown in the diagram below.

InputStream

AudioInputStream SequenceInputStream

For Reading Audio data For Reading from a

Sequence of Streams

FileInputStream ByteArrayInputStream

For Reading from a File For Reading from a byte Array

ObjectInputStream PipedInputStream

For Reading Objects from a Stream For Reading from a Piped Stream

FilterInputStream

For Filtering Input From an
Existing Stream

We will be using the FileInputStream class in Chapter 10 Writing Files , and the
ObjectInputStream class in Chapter 11 Reading Files .

The FilterInputStream class has a further nine direct subclasses that provide more specialized ways of
filtering or transforming data from an input stream. We will only be using the BufferedInputStream
class, but here's the complete set with an indication of what each of them does:

BufferedInputStream

Buffers input from another stream in memory to make the read
operations more efficient.

DataInputStream Reads data of primitive types from a binary stream.

CheckedInputStream Reads an input stream and maintains a checksum for the data

that is read to verify its integrity.