File Handling in Java

import java.io.File;

File file = new File("notes.txt");
System.out.println("Exists: " + file.exists());
System.out.println("Name: " + file.getName());
System.out.println("Path: " + file.getAbsolutePath());
System.out.println("Is File: " + file.isFile());
System.out.println("Is Directory: " + file.isDirectory());

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

try (FileWriter writer = new FileWriter("notes.txt")) {
    writer.write("Hello, Java File Handling!\n");
    writer.write("This is line 2.\n");
    System.out.println("File written successfully.");
} catch (IOException e) {
    System.out.println("Error: " + e.getMessage());
}

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

try (BufferedReader reader = new BufferedReader(new FileReader("notes.txt"))) {
    String line;
    while ((line = reader.readLine()) != null) {
        System.out.println(line);
    }
} catch (IOException e) {
    System.out.println("Error: " + e.getMessage());
}

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

List<String> lines = Files.readAllLines(Path.of("notes.txt"));
lines.forEach(System.out::println);

try (FileWriter writer = new FileWriter("notes.txt", true)) { // true = append
    writer.write("This line is appended.\n");
}

File file = new File("temp.txt");
if (file.delete()) {
    System.out.println("Deleted: " + file.getName());
} else {
    System.out.println("Failed to delete.");
}

import java.io.*;

class Student implements Serializable {
    String name;
    int age;
    Student(String name, int age) { this.name = name; this.age = age; }
}

// Write object
try (ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("student.dat"))) {
    out.writeObject(new Student("Alice", 20));
}

// Read object
try (ObjectInputStream in = new ObjectInputStream(new FileInputStream("student.dat"))) {
    Student s = (Student) in.readObject();
    System.out.println(s.name + " - " + s.age);
}

import java.io.*;
import java.util.Scanner;

public class NotesApp {
    static final String FILE = "my_notes.txt";

    public static void main(String[] args) throws IOException {
        Scanner sc = new Scanner(System.in);
        boolean running = true;

        while (running) {
            System.out.println("\n1. Add Note  2. View Notes  3. Exit");
            int choice = sc.nextInt(); sc.nextLine();

            switch (choice) {
                case 1:
                    System.out.print("Enter note: ");
                    String note = sc.nextLine();
                    try (FileWriter fw = new FileWriter(FILE, true)) {
                        fw.write(note + "\n");
                    }
                    System.out.println("Note saved!");
                    break;
                case 2:
                    try (BufferedReader br = new BufferedReader(new FileReader(FILE))) {
                        String line;
                        System.out.println("=== YOUR NOTES ===");
                        while ((line = br.readLine()) != null) System.out.println("• " + line);
                    } catch (FileNotFoundException e) {
                        System.out.println("No notes yet.");
                    }
                    break;
                case 3: running = false; break;
            }
        }
        sc.close();
    }
}