📁 Java File Handling – Read, Write, Delete, and Create Files

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🧲 Introduction – Why File Handling is Crucial in Java

In any real-world application, storing and retrieving data from files is a critical operation — from logs and reports to user-generated content and configurations. Java provides robust tools to handle file operations such as reading, writing, creating, deleting, and modifying files, all under the java.io and java.nio.file packages.

✅ In this guide, you’ll learn:

• How to work with files in Java
• File creation, reading, writing, and deletion
• Using File, FileWriter, FileReader, BufferedReader, and Files class
• Best practices for file handling and exception management

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🔑 Java File Handling Packages

Java provides two primary packages for file operations:

Package	Description
java.io	Legacy file handling classes (File, FileReader)
java.nio.file	Modern, more efficient API with Path, Files

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📦 Creating a File in Java

✅ Using File Class

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

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

✅ Explanation:

• createNewFile() creates a new file if it doesn’t exist.
• Handles IOException using try-catch.

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📖 Writing to a File in Java

✅ Using FileWriter

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

public class WriteFile {
    public static void main(String[] args) {
        try {
            FileWriter writer = new FileWriter("example.txt");
            writer.write("Hello, Java File Handling!");
            writer.close();
            System.out.println("Successfully wrote to the file.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

✅ Explanation:

• FileWriter writes characters to a file.
• Always close the writer using close() to flush and free resources.

💡 Tip: Use BufferedWriter for better performance on large data writes.

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📄 Reading from a File in Java

✅ Using FileReader and BufferedReader

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

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

✅ Explanation:

• BufferedReader reads text efficiently line by line.
• readLine() returns null when the end of the file is reached.

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❌ Deleting a File in Java

import java.io.File;

public class DeleteFile {
    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.");
        }
    }
}

✅ Explanation:

• delete() returns true if file deletion is successful.

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⚡ Modern File Handling – java.nio.file.Files

✅ Creating and Writing in One Step

import java.nio.file.*;
import java.io.IOException;
import java.util.List;

public class ModernFileWrite {
    public static void main(String[] args) throws IOException {
        Path path = Paths.get("modern.txt");
        Files.write(path, List.of("Line 1", "Line 2"), StandardOpenOption.CREATE);
    }
}

✅ Explanation:

• Files.write() is more concise.
• Supports multiple lines with List.of().

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✅ Reading All Lines at Once

List<String> lines = Files.readAllLines(Paths.get("modern.txt"));
lines.forEach(System.out::println);

💡 Note: Ideal for small to medium files.

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✅ Checking If a File Exists

Path path = Paths.get("modern.txt");
if (Files.exists(path)) {
    System.out.println("File exists!");
}

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🔐 Handling File Permissions and Properties

✅ Getting File Info

File file = new File("example.txt");
System.out.println("File name: " + file.getName());
System.out.println("Absolute path: " + file.getAbsolutePath());
System.out.println("Writable: " + file.canWrite());
System.out.println("Readable: " + file.canRead());
System.out.println("File size in bytes: " + file.length());

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💡 Best Practices for File Handling

• ✅ Always close streams (FileReader, FileWriter, etc.)
• ✅ Use try-with-resources to auto-close resources
• ✅ Check file existence before reading/deleting
• ✅ Use java.nio.file for modern projects
• ❗ Handle exceptions properly to avoid crashing apps

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📌 Summary – Mastering Java File Handling

Java provides a powerful and flexible set of APIs to handle file operations — essential for developing real-world applications that require data persistence, logging, or report generation. Whether you’re creating a log file, saving user data, or processing configuration files, Java’s file handling capabilities make it all possible.

🧾 Key Takeaways:

• ✅ Use File class for basic operations like creation, deletion, and info retrieval
• ✅ Use FileReader, FileWriter, and BufferedReader for traditional I/O
• ✅ Prefer java.nio.file.Files and Path for modern, cleaner file operations
• ✅ Always handle exceptions and close file resources properly
• ✅ Apply try-with-resources and null-safety checks for production-grade reliability

From basic file creation to stream-based file writing, this guide equips you with the tools and examples needed to confidently manage files in Java.

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❓FAQs – Java File Handling

❓ What is the difference between FileWriter and BufferedWriter?

BufferedWriter provides buffering for FileWriter, which improves write performance for large files.

❓ Which package is preferred: java.io or java.nio.file?

java.nio.file is more modern, efficient, and recommended for new applications.

❓ How can I read a file line-by-line?

Use BufferedReader.readLine() inside a loop until it returns null.

❓ How to check if a file exists in Java?

Use new File("filename").exists() or Files.exists(Path).

❓ How to write multiple lines to a file?

Use Files.write(Path, List<String>) or write manually using BufferedWriter.

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