GUI Java Buttons not resizing?

import java.awt.ComponentOrientation;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import java.awt.GridBagConstraints;
import javax.swing.JFrame;
import java.util.Scanner;
import javax.swing.JPanel;
import java.awt.GridLayout;

public class DisplayBoard2 {
public static void addButtons(JPanel panel, GameOfLife game, GridBagConstraints constraints){
/*
This is supposed to be part of the GUI for Conway's game of Life, but the other classes used(GameOfLife and Board) have no issues and the methods used all return proper values. 
*/
		JButton button;
		panel.setLayout(new GridLayout());
		for(int x =0; x<game.getBoard().getRow(); x++){
			for(int y = 0; y<game.getBoard().getCol(); y++){
				button = new JButton();
				constraints.fill = GridBagConstraints.BOTH;
				constraints.gridx = x;
				constraints.gridy = y;
				panel.add(button, constraints);
			}
		}
	}
	
	public static void showGui(){
        Scanner scan = new Scanner(System.in);
        GameOfLife game = new GameOfLife();
        GridBagConstraints constraints = new GridBagConstraints();
        game.createBoard(scan);
        JFrame frame = new JFrame();
        JPanel panel = new JPanel();
        frame.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new GridBagLayout());
        constraints.fill = GridBagConstraints.BOTH;
        frame.setSize(400, 400);
        DisplayBoard.addButtons(panel, game, constraints);
        frame.add(panel);
        frame.setVisible(true);      
        }



	public static void main(String[] args){
            	DisplayBoard.showGui();
            	}
		;
	}