How can we create a login form in Java?\\n

We can develop a login form in Java using Java Swing technology. In this example, we can create two labels username and password, two text fields for the user to enter valid credentials, and finally, one submit button. Once the user is able to enter the valid credentials in the two text fields, we can able to see Hello admin in the login form.

Setting Up the Project

We'll use Java Swing, a GUI toolkit for building desktop applications.

Required Libraries are:

• javax.swing.* (for Swing components)
  
• java.awt.* (for layout management)

Components Required

To create a login form, we'll need several basic Swing components:

• JPanel: Container for organizing components.
  
• JLabel: Text labels for username and password fields.
  
• JTextField: Input field for username.
  
• JPasswordField: Secure input field for password.
  
• JButton: Submit and cancel buttons.

Approach

The following are the main steps to create a login form in Java:

Class Setup

Extends JFrame (for the window) and implements ActionListener (for button clicks).

public class LoginDemo extends JFrame implements ActionListener {
}

UI Components

Labels: Displays non-editable text

• user_label ? "User Name :"
  
• password_label ? "Password :"
  
• message ? Displays login status.

user_label = new JLabel();
user_label.setText("User Name :");
password_label = new JLabel();
password_label.setText("Password :");
message = new JLabel();

Input Fields: Allows user text input (visible/hidden)

• userName_text (JTextField) ? Takes username input.
  
• password_text (JPasswordField) ? Takes password (hidden input).

userName_text = new JTextField();
password_text = new JPasswordField();

Button: Triggers actions when clicked

• submit ? Triggers login validation.

submit = new JButton("SUBMIT");

Constructor (LoginDemo())

Sets up the panel with GridLayout (3 rows, 1 column).

panel = new JPanel(new GridLayout(3, 1));

Configures the JFrame:

• Title: "Please Login Here !"
  
• Size: 450x350
  
• Closes on EXIT.

setTitle("Please Login Here !");
setSize(450,350);
setVisible(true);

Event Handling

Implements ActionListener interface, submit button triggers actionPerformed method, and validates entered username and password.

if (userName.trim().equals("admin") && password.trim().equals("admin")) {
         message.setText(" Hello " + userName + "");
      } 
else {
         message.setText(" Invalid user.. ");
      }

Main Method

Launches the app by creating a LoginDemo object.

public static void main(String[] args) {
      new LoginDemo();
}

Example

Below is an example to create a login form in Java:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LoginDemo extends JFrame implements ActionListener {
   JPanel panel;
   JLabel user_label, password_label, message;
   JTextField userName_text;
   JPasswordField password_text;
   JButton submit, cancel;
   LoginDemo() {
      // Username Label
      user_label = new JLabel();
      user_label.setText("User Name :");
      userName_text = new JTextField();
      // Password Label
      password_label = new JLabel();
      password_label.setText("Password :");
      password_text = new JPasswordField();
      // Submit
      submit = new JButton("SUBMIT");
      panel = new JPanel(new GridLayout(3, 1));
      panel.add(user_label);
      panel.add(userName_text);
      panel.add(password_label);
      panel.add(password_text);
      message = new JLabel();
      panel.add(message);
      panel.add(submit);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      // Adding the listeners to components..
      submit.addActionListener(this);
      add(panel, BorderLayout.CENTER);
      setTitle("Please Login Here !");
      setSize(450,350);
      setVisible(true);
   }
   public static void main(String[] args) {
      new LoginDemo();
   }
   @Override
   public void actionPerformed(ActionEvent ae) {
      String userName = userName_text.getText();
      String password = password_text.getText();
      if (userName.trim().equals("admin") && password.trim().equals("admin")) {
         message.setText(" Hello " + userName + "");
      } else {
         message.setText(" Invalid user.. ");
      }
   }
}

Output