File Handling in Java (Complete Guide for Beginners)

File handling in Java is used to create, read, write, update, and delete files.
It is very important for building real-world applications like logging systems, data storage, reports, etc.

What is File Handling?

File handling means working with files stored on your computer.
Java provides built-in classes in the java.io package for this.

Important Classes in Java File Handling

Class	Purpose
File	Create & manage files
FileWriter	Write data to file
FileReader	Read data from file
BufferedWriter	Efficient writing
BufferedReader	Efficient reading
PrintWriter	Formatted writing
Scanner	Read file easily

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1. Creating a File

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

class Main {
    public static void main(String[] args) {
        try {
            File file = new File("test.txt");

            if (file.createNewFile()) {
                System.out.println("File created: " + file.getName());
            } else {
                System.out.println("File already exists");
            }

        } catch (IOException e) {
            System.out.println("Error occurred");
        }
    }
}

2. Writing to a File

Using FileWriter

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

class Main {
    public static void main(String[] args) {
        try {
            FileWriter writer = new FileWriter("test.txt");
            writer.write("Hello, this is Java File Handling!");
            writer.close();

            System.out.println("Data written successfully");

        } catch (IOException e) {
            System.out.println("Error writing file");
        }
    }
}

Using BufferedWriter (Faster)

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

class Main {
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new FileWriter("test.txt"));

        bw.write("Buffered writing example");
        bw.newLine();
        bw.write("Second line");

        bw.close();
    }
}

Using PrintWriter (Formatted Output)

import java.io.PrintWriter;

class Main {
    public static void main(String[] args) throws Exception {
        PrintWriter pw = new PrintWriter("test.txt");

        pw.println("Name: Ponvel");
        pw.println("Score: 95");

        pw.close();
    }
}

3. Reading from a File

Using FileReader

import java.io.FileReader;

class Main {
    public static void main(String[] args) throws Exception {
        FileReader fr = new FileReader("test.txt");
        int i;

        while ((i = fr.read()) != -1) {
            System.out.print((char)i);
        }

        fr.close();
    }
}

Using BufferedReader (Efficient)

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

class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new FileReader("test.txt"));
        String line;

        while ((line = br.readLine()) != null) {
            System.out.println(line);
        }

        br.close();
    }
}

Using Scanner (Simple Way)

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

class Main {
    public static void main(String[] args) throws Exception {
        File file = new File("test.txt");
        Scanner sc = new Scanner(file);

        while (sc.hasNextLine()) {
            System.out.println(sc.nextLine());
        }

        sc.close();
    }
}

4. Deleting a File

import java.io.File;

class Main {
    public static void main(String[] args) {
        File file = new File("test.txt");

        if (file.delete()) {
            System.out.println("File deleted successfully");
        } else {
            System.out.println("Failed to delete file");
        }
    }
}

5. File Methods (Must Know)

Method	Description
createNewFile()	Creates a new file
exists()	Checks file exists
delete()	Deletes file
getName()	Returns file name
getAbsolutePath()	Returns full path
length()	Returns file size
canRead()	Check read permission
canWrite()	Check write permission

Example

File file = new File("test.txt");

System.out.println(file.getName());
System.out.println(file.getAbsolutePath());
System.out.println(file.length());
System.out.println(file.canRead());

Exception Handling in File Handling

File operations may throw errors (IOException)

try {
    // file code
} catch (IOException e) {
    System.out.println("Error: " + e.getMessage());
}

Advantages of File Handling

✔ Store data permanently
✔ Useful for logs & reports
✔ Helps in real applications

Disadvantages

Slower than memory
Requires exception handling

Conclusion

File handling is a must-know concept in Java for real-world development.

Create files
Read & write data
Manage file operations