Create GUI application, by instantiating outer class of JFrame.

This example demonstrate how to create GUI for Java Application, by instantiating outer class of JFrame.

Create a class OuterJFrame.java, extends JFrame.

package javajframeapplication;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;

public class OuterJFrame extends JFrame{
    
    public OuterJFrame(){
            this.setTitle("Java-Buddy");
            this.setSize(300, 200);
            this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            
            JButton buttonExit = new JButton("Exit");
            buttonExit.addActionListener(new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent e) {
                    System.exit(0);
                }
            });
            
            this.add(buttonExit);
    }
}

Modify main class, instantiate OuterJFrame class in main() method.

package javajframeapplication;

import javax.swing.SwingUtilities;

/**
 *
 * @web http://java-buddy.blogspot.com/
 */
public class JavaJFrameApplication {
    
    public static void main(String[] args) {
        
        SwingUtilities.invokeLater(new Runnable(){

            @Override
            public void run() {
                
                OuterJFrame myOuterJFrame = new OuterJFrame();
                myOuterJFrame.setVisible(true);
            }
        });
    }
}

We can also implement our custom JFrame as inner class. Refer:

• Create GUI application, by instantiating static inner class of JFrame.
• Create GUI application, by instantiating non-static inner class of JFrame.