What is File Handling in Java?

File Handling in Java allows you to create, read, write, update, and delete files using the java.io and java.nio packages.

Commonly used classes:

• File
• FileWriter / BufferedWriter
• FileReader / BufferedReader
• Scanner
• PrintWriter
• Files (from java.nio.file)

Common File Operations

Example 1: Create a File

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

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

Example 2: Write to a File

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

public class WriteFileExample {
    public static void main(String[] args) {
        try {
            FileWriter writer = new FileWriter("example.txt");
            writer.write("Hello, this is Java file handling!\nLet's learn it.");
            writer.close();
            System.out.println("Successfully wrote to the file.");
        } catch (IOException e) {
            System.out.println("An error occurred.");
            e.printStackTrace();
        }
    }
}

Example 3: Read from a File

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ReadFileExample {
    public static void main(String[] args) {
        try {
            File file = new File("example.txt");
            Scanner reader = new Scanner(file);
            while (reader.hasNextLine()) {
                String line = reader.nextLine();
                System.out.println(line);
            }
            reader.close();
        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
            e.printStackTrace();
        }
    }
}

Example 4: Delete a File

import java.io.File;

public class DeleteFileExample {
    public static void main(String[] args) {
        File file = new File("example.txt");
        if (file.delete()) {
            System.out.println("Deleted the file: " + file.getName());
        } else {
            System.out.println("Failed to delete the file.");
        }
    }
}

Additional: Using BufferedReader for Efficient Reading

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class BufferedReaderExample {
    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new FileReader("example.txt"));
            String line;
            while ((line = br.readLine()) != null) {
                System.out.println(line);
            }
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Best Practices

• Always close file streams after use (.close()).
• Use try-with-resources (Java 7+) for automatic closing.
• Handle exceptions like IOException or FileNotFoundException.
• Use buffered readers/writers for large files.