Java I/O Fundamentals

1. Introduction

The Java I/O (Input/Output) API provides a standard way to read and write data to files, network connections, and other resources. It includes classes and interfaces for handling binary and character data.

2. Java I/O Overview

Java I/O consists of two main categories:

• Byte Streams: Handle raw binary data.
• Character Streams: Handle character data (text).

Java I/O is primarily represented by the java.io package.

3. Streams

Streams in Java are used to read and write data. They can be categorized as:

3.1 Byte Streams

Byte streams use InputStream and OutputStream as their base classes.

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class ByteStreamExample {
    public static void main(String[] args) {
        try (FileOutputStream fos = new FileOutputStream("example.txt")) {
            fos.write(65); // Writes 'A'
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

3.2 Character Streams

Character streams use Reader and Writer as their base classes.

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class CharStreamExample {
    public static void main(String[] args) {
        try (FileWriter fw = new FileWriter("example.txt")) {
            fw.write("Hello, World!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

4. File Handling

Java provides the File class in the java.io package for file manipulation. It allows checking file properties and performing operations like creating, deleting, or renaming files.

import java.io.File;
import java.io.IOException;

public class FileHandlingExample {
    public static void main(String[] args) {
        File file = new File("example.txt");
        try {
            if (file.createNewFile()) {
                System.out.println("File created: " + file.getName());
            } else {
                System.out.println("File already exists.");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

5. Best Practices

Here are some best practices for Java I/O:

• Always close your streams using try-with-resources to avoid memory leaks.
• Use buffered streams for better performance when reading or writing large amounts of data.
• Handle exceptions properly to avoid application crashes.

6. FAQ