java - JFrame class not working in Main

I'm trying to write a Java program that declares a JFrame class and creates an object of that class in the main. For the life of me I cannot get the JFrame title, JPanel, and JButtons to appear when I create the "MyButtons" object in the main. All I get is a blank JPanel.

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

class MyButtons extends JFrame

{
    public MyButtons()
    {
        JFrame frame = new JFrame("MyButtons");
        JPanel panel = new JPanel();
        frame.add(panel);

        JButton b1 = new JButton("Button 1");
        JButton b2 = new JButton("Button 2");


        panel.add(b1);
        panel.add(b2);     
    }      
}

class TestMyButtons
{
    public static void main(String [] args)
    {
       MyButtons go = new MyButtons();

       go.setSize(200,75);
       go.setLocation(200,300);
       go.setVisible(true);
       go.setResizable(true);
       go.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }   
}

Answer

As you extend JFrame so you don't need to create another JFrame instance at constructor. Simply add panel to MyButtons which already inherited JFrame.

public MyButtons(){

    //JFrame frame = new JFrame("MyButtons"); Commentted this
    JPanel panel = new JPanel();
    //frame.add(panel); And this

    JButton b1 = new JButton("Button 1");
    JButton b2 = new JButton("Button 2");


    panel.add(b1);
    panel.add(b2); 
    add(panel); // Add panel to MyButtons frame    
}