📝 “Build a Simple Notepad in Java (With Save & Open!) — Better Than Windows Notepad?!”

Tired of plain old Notepad? Let’s build your own version — in just one Java file!
This beginner-friendly project is perfect for practicing Java Swing, file handling, and event-driven programming.
By the end, you’ll have a fully functional text editor with a modern feel!

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🧠 What You’ll Learn:

• Create a basic GUI with JFrame and JTextArea
• Use a JMenuBar for File operations like Open, Save, New, and Exit
• Handle text files with BufferedReader and BufferedWriter
• Center and resize your app window

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📦 Full Java Code: SimpleNotepad.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;

public class SimpleNotepad extends JFrame implements ActionListener {

    JTextArea textArea;
    JFileChooser fileChooser;
    File currentFile;

    public SimpleNotepad() {
        setTitle("Java Notepad - Devesh Edition");
        setSize(800, 600);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null); // Center the window

        textArea = new JTextArea();
        JScrollPane scrollPane = new JScrollPane(textArea);
        add(scrollPane);

        createMenuBar();

        fileChooser = new JFileChooser();

        setVisible(true);
    }

    private void createMenuBar() {
        JMenuBar menuBar = new JMenuBar();

        JMenu fileMenu = new JMenu("File");

        JMenuItem newItem = new JMenuItem("New");
        JMenuItem openItem = new JMenuItem("Open...");
        JMenuItem saveItem = new JMenuItem("Save");
        JMenuItem exitItem = new JMenuItem("Exit");

        newItem.addActionListener(this);
        openItem.addActionListener(this);
        saveItem.addActionListener(this);
        exitItem.addActionListener(this);

        fileMenu.add(newItem);
        fileMenu.add(openItem);
        fileMenu.add(saveItem);
        fileMenu.addSeparator();
        fileMenu.add(exitItem);

        menuBar.add(fileMenu);
        setJMenuBar(menuBar);
    }

    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();

        switch (command) {
            case "New":
                textArea.setText("");
                currentFile = null;
                setTitle("Java Notepad - New File");
                break;

            case "Open...":
                int openResult = fileChooser.showOpenDialog(this);
                if (openResult == JFileChooser.APPROVE_OPTION) {
                    currentFile = fileChooser.getSelectedFile();
                    openFile(currentFile);
                }
                break;

            case "Save":
                if (currentFile == null) {
                    int saveResult = fileChooser.showSaveDialog(this);
                    if (saveResult == JFileChooser.APPROVE_OPTION) {
                        currentFile = fileChooser.getSelectedFile();
                    }
                }
                if (currentFile != null) {
                    saveFile(currentFile);
                }
                break;

            case "Exit":
                System.exit(0);
                break;
        }
    }

    private void openFile(File file) {
        try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
            textArea.read(reader, null);
            setTitle("Java Notepad - " + file.getName());
        } catch (IOException ex) {
            showError("Could not open file.");
        }
    }

    private void saveFile(File file) {
        try (BufferedWriter writer = new BufferedWriter(new FileWriter(file))) {
            textArea.write(writer);
            setTitle("Java Notepad - " + file.getName());
        } catch (IOException ex) {
            showError("Could not save file.");
        }
    }

    private void showError(String message) {
        JOptionPane.showMessageDialog(this, message, "Error", JOptionPane.ERROR_MESSAGE);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(SimpleNotepad::new);
    }
}

🔍 Line-by-Line Breakdown

🖼️ GUI Setup

public class SimpleNotepad extends JFrame implements ActionListener {

This defines our main class, extending JFrame (for the GUI window) and implementing ActionListener (for handling menu actions)

JTextArea textArea = new JTextArea();
JScrollPane scrollPane = new JScrollPane(textArea);
add(scrollPane);

Creates a large text editing area with scrollbars.

setTitle("Java Notepad - Devesh Edition");
setSize(800, 600);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocationRelativeTo(null);

Basic window setup — sets title, size, close behavior, and centers the window on screen.

📂 File Menu & Items

JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");

Creates a menu bar with a File menu.

JMenuItem newItem = new JMenuItem("New");
newItem.addActionListener(this);

Adds menu items and connects them to the main class via ActionListener.

🎯 Action Handler

public void actionPerformed(ActionEvent e) {
    String command = e.getActionCommand();

This method is triggered whenever a menu item is clicked. It checks the label (command) to decide what to do.

case "New":
    textArea.setText(""); // Clear text

Resets the editor for a new file.

case "Open...":
    fileChooser.showOpenDialog(this);
    openFile(file);

Opens a file using JFileChooser and loads its contents into the editor.

case "Save":
    fileChooser.showSaveDialog(this);
    saveFile(file);

Lets the user pick a location and saves the text to the file.

case "Exit":
    System.exit(0);

Closes the app.

🧠 Helper Methods

private void openFile(File file)
private void saveFile(File file)
private void showError(String message)