CODE EXAMPLE FOR JAVA

append button jframe

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

public class MyFrame {
  
MyFrame() 
  
     	JFrame frame = new JFrame("Title");

  		frame.setTitle("JFrame title"); // Frame title
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Exit out of app
        frame.setResizable(true); // Prevent frame from being resized, or not
        frame.setSize(500,500); // Sets x and y 
        frame.setVisible(true); //makes frame visible
  
		button = new JButton(); // creates button

 		Border border = BorderFactory.createLineBorder(Color.green, 3); // specifies border

        button.setBounds(200, 100, 100, 50); // button properties
        button.setBorder(border); // gives button border
        button.setText("A nice button"); // button text

		MyFrame.add(button); //adds button to frame
   
}}