Java Program to Display Message in New Frame

Problem Description

We have to write a program in Java such that it creates a frame with a button. When the button is clicked, a message is displayed in a new frame.

Expected Input and Output

For displaying a message in a new frame, we can have the following different sets of input and output.

1. To View the Original Frame :

On every execution of the program, 
it is expected that a frame with a button is created.

2. To View the Message in a New Frame :

On click of the button, 
it is expected that "!!! Hello !!!" message is displayed in a new frame.

Problem Solution

1. Create the original frame and add a button to it.
2. Add ActionListener to the button.
3. Display the original frame.
4. When the button is clicked, create a new frame and add a message to the frame.
5. Display the new frame.

Program/Source Code

Here is source code of the Java Program to display a message in a new frame. The program is successfully compiled and tested using javac compiler on Fedora 30. The program output is also shown below.

/* Java Program to Display a Message in a New Frame */
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class Message implements ActionListener
{
    //Function to create the original frame
    public static void main(String args[])
    {
    //Create a frame
    JFrame frame = new JFrame("Original Frame");
    frame.setSize(300,300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


    //Create an object
    Message obj = new Message();


    //Create a button to view message
    JButton button = new JButton("View Message");
    frame.add(button);
    button.addActionListener(obj);


    //View the frame
    frame.setVisible(true);
    }
    //Function to create a new frame with message
    public void actionPerformed(ActionEvent e)
    {
    //Create a new frame
    JFrame sub_frame = new JFrame("Sub Frame");
    sub_frame.setSize(200,200);


    //Display the message
    JLabel label = new JLabel("!!! Hello !!!");
    sub_frame.add(label);


    //View the new frame
    sub_frame.setVisible(true);
    }
}

1. To create a frame, use the JFrame class.
2. To create a button, use the JButton class.
3. Add ActionListener to the button.

Runtime Test Cases

Here’s the run time test cases to display message a in new frame for different input cases.

Test case 1 – To View the Original Frame.

Test case 2 – To View the Message in New Frame.