Java IO (Input/Output) is a pre-defined package in Java used for performing various input/output operations. It provides a set of classes to read and write data from/to various sources such as files, network connections, and memory buffers.
Example:
One of the most common example of Java I/O is reading and writing data to a file. This could be implemented as follows:
// Writing Data to a File:
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class WriteToFile {
public static void main(String[] args) {
try {
String content = “This is the data we’re writing to a file.”;
File file = new File(“example.txt”);
FileWriter writer = new FileWriter(file);
writer.write(content);
writer.close();
} catch (IOException e) {
System.out.println(“An error occurred while writing to the file.”);
e.printStackTrace();
}
}
}
// Reading Data from a File:
import java.io.File;
import java.util.Scanner;
public class ReadFile {
public static void main(String[] args) {
try {
File file = new File(“example.txt”);
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
System.out.println(line);
}
scanner.close();
} catch (IOException e) {
System.out.println(“An error occurred while reading from the file.”);
e.printStackTrace();
}
}
}
In this example, we create a file object and use FileWriter to write data to a file. We then use Scanner to read the data from the file.
Java IO stands for Java Input/Output and is a collection of classes and interfaces that provide support for performing input/output operations in Java.
Java IO provides two types of APIs: the classic stream-based IO APIs and the NIO (New Input/output) APIs that support non-blocking IO operations.
The classic stream-based IO APIs consist of classes like InputStream, OutputStream, Reader, and Writer, which are implemented through byte and character streams.
The NIO APIs consist of classes like Channels, Buffers, and Selectors, which are implemented through buffer and channel-based architecture, allowing for better performance.
The key classes and interfaces that are used in Java IO include File, FileDescriptor, RandomAccessFile, FileReader, FileWriter, ByteArrayInputStream, ByteArrayOutputStream, InputStreamReader, OutputStreamWriter, BufferedReader, BufferedWriter, DataInputStream, DataOutputStream, ObjectOutputStream, ObjectInputStream, among others.
Java IO also provides support for file operations like reading, writing, copying, moving, deleting, and creating files and directories.
Java IO includes support for compressing and decompressing files using compression formats like GZip or Zip.
Error handling, exceptions, and synchronization play a crucial role in Java IO to ensure smoother input/output operations.
Java IO also provides support for network programming through classes like Socket, ServerSocket, and DatagramSocket.
The latest version of Java IO includes enhancements like the NIO.2 APIs that provide support for file system operations, which make it easier to work with files, directories, and symbolic links on a file system.
What is the difference between InputStream and Reader in Java IO?
Answer: InputStream is used to read binary data such as images or videos while Reader is used to read character data such as text files.
What is the purpose of FileWriter class in Java IO?
Answer: FileWriter is used to write text data to a file in Java. It is a subclass of Writer class.
What is the difference between FileInputStream and BufferedInputStream in Java IO?
Answer: FileInputStream is used to read binary data such as images or videos while BufferedInputStream is used to improve performance by buffering the input data in memory.
What is the purpose of RandomAccessFile class in Java IO?
Answer: RandomAccessFile is used to read and write data to a file at a specific position. It allows the data to be accessed randomly rather than sequentially.
What is the difference between FileOutputStream and PrintWriter in Java IO?
Answer: FileOutputStream is used to write binary data such as images or videos while PrintWriter is used to write character data such as text files. PrintWriter provides additional formatting support for writing text data.