The java.io package is the original I/O API introduced in JDK 1.0. It provides a comprehensive set of classes and interfaces for performing input and output operations. It includes mechanisms for reading from and writing to files, handling data streams, and dealing with serialization.
Key Components of java.io:
Streams:
- Byte Streams: These streams handle raw binary data. The primary classes are InputStream and OutputStream, with subclasses like FileInputStream, FileOutputStream, BufferedInputStream, and BufferedOutputStream. These are used for reading and writing byte data from files or other sources.
- Character Streams: These streams handle data in character format and are designed for text processing. The primary classes are Reader and Writer, with subclasses like FileReader, FileWriter, BufferedReader, and BufferedWriter. They provide convenient methods for reading and writing text.
File Handling:
- File Class: The File class represents file and directory pathnames. It provides methods for file manipulation such as creating, deleting, and checking file properties.
- RandomAccessFile: This class allows reading from and writing to a file at any position, providing a way to access file data randomly.
Serialization:
- The Serializable interface and ObjectInputStream/ObjectOutputStream classes enable the serialization and deserialization of objects, allowing objects to be converted to a byte stream and vice versa.
Advantages of java.io:
- Mature and well-established.
- Easy to use for basic file and stream operations.
- Provides a wide range of functionalities for different I/O needs.
Limitations of java.io:
- It uses blocking I/O, which may not be efficient for high-performance applications.
- Limited support for modern features like non-blocking I/O.
The java.io package is one of the core Java packages that provides a powerful and flexible framework for input and output (I/O) operations. It enables programs to read data from various input sources (such as files, keyboard, memory) and write data to different output destinations (such as files, console, or network connections).