Creating a grid layout that holds 100 buttons with 80 empty buttons and 20 random treasure buttons

We are working on a Treasure Hunt game in class as a project. Below is the code that we have so far. I need to randomize where the Treasure Buttons are. My question is: Do I need to create an array that will hold EmptyButton and TreasureButton and then call Random on it or is there a way to create a random layout within the TreasureButton class?

Here is our code so far

public class TreasureGame
{
    // has-a number of tries
    private int numberOfTriesLeft = 50;
    //has-a number of hidden treasure
    private int numberStillHidden = 20;
    // Purpose: Subtract 1 try for every attempt taken by the player
    public void reduceTriesLeft()
    {
        numberOfTriesLeft -= 1;
    }
    
    public void reduceNumberStillHidden()
    {
        numberStillHidden -=1;
    }
    
    public int getNumberStillHidden()
    {
        return numberStillHidden;
    }
    
    public int getNumberOfTriesLeft()
    {
        return numberOfTriesLeft;
    }
}

import java.awt.*;
import javax.swing.*;
import java.util.Random;
public class TreasureGameView extends JFrame
{
    // has-a TreasureGame
    private TreasureGame treasureGame;
    //has-a triesLeftField
    private JTextField triesLeftField;
    //has-a treasures left field
    private JTextField treasuresLeftField;
    private JTextField lastMoveField;
    
    public TreasureGameView(TreasureGame newTreasureGame)
    {
        treasureGame = newTreasureGame;
        setTitle("Treasure Hunt");
        setSize(800, 500);
        setLayout(new BorderLayout());
        
        JPanel gridPanel = new JPanel();
        gridPanel.setLayout(new GridLayout(10, 10));
        add(gridPanel, BorderLayout.CENTER);
    
        
        
        for(int counter=0; counter<treasureGame.getNumberStillHidden(); counter++)
        {
            
            gridPanel.add(new TreasureButton(treasureGame, this));
            
        }
        for(int counter=0; counter<(10*10)-treasureGame.getNumberStillHidden(); counter++)
        {
            
            gridPanel.add(new EmptyButton(treasureGame, this));
        }

    
        
        JPanel triesLeftPanel = new JPanel();
        
        JLabel triesLeftLabel = new JLabel("Tries left:");
        triesLeftPanel.add(triesLeftLabel);
        triesLeftField = new JTextField("" + treasureGame.getNumberOfTriesLeft());
        triesLeftPanel.add(triesLeftField);
        JLabel treasuresLeftLabel = new JLabel("Treasures left:");
        triesLeftPanel.add(treasuresLeftLabel);
        treasuresLeftField = new JTextField("" + treasureGame.getNumberStillHidden());
        triesLeftPanel.add(treasuresLeftField);
        
        
        add(triesLeftPanel, BorderLayout.WEST);
        
        JPanel lastMovePanel = new JPanel();
        JLabel lastMoveLabel = new JLabel("Your last move was: ");
        lastMovePanel.add(lastMoveLabel);
        lastMoveField = new JTextField("" );
        lastMovePanel.add(lastMoveField);
        add(lastMovePanel, BorderLayout.SOUTH);
        
        
        
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }
    
    //Purpose; Update Value of triesLeftField
    public void updateUI()
    {
        triesLeftField.setText("" + treasureGame.getNumberOfTriesLeft());
        treasuresLeftField.setText("" + treasureGame.getNumberStillHidden());
    }
}

import javax.swing.*;
public class EmptyButton extends JButton
{
    //has-a TreasureGame
    private TreasureGame game;
    
    //has-a TreasureGameView
    private TreasureGameView gameView;
    public EmptyButton(TreasureGame game, TreasureGameView gameView)
    {
        super();
        this.game = game;
        this.gameView = gameView;
        //setText("?");
        addActionListener(new EmptyButtonListener(this, game, gameView));
    }
}

public class TreasureButton extends EmptyButton
{
   public TreasureButton(TreasureGame game, TreasureGameView gameView)
   {
       super(game, gameView);
       
       //setText("T"); 
       addActionListener(new TreasureButtonListener(this, game, gameView));
   }
   
}

import java.awt.event.*;
public class EmptyButtonListener implements ActionListener
{
    private EmptyButton button;
    //has-a TreasureGame
    private TreasureGame  game;
    //has-a TreasureGameView
    private TreasureGameView gameView;
    
    public EmptyButtonListener(EmptyButton button, TreasureGame game, TreasureGameView gameView)
    {
        this.game = game;
        this.button = button;
        this.gameView = gameView;
    }
    
    public void actionPerformed(ActionEvent e)
    {
        //button.setText("X");
        button.setEnabled(false);
        game.reduceTriesLeft();
        gameView.updateUI();
    }
}

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TreasureButtonListener implements ActionListener
{
    // Has-a TreasureButton
    private TreasureButton button;
    private TreasureGame game;
    private TreasureGameView gameView;
    
    public TreasureButtonListener(TreasureButton button, TreasureGame game, TreasureGameView gameView)
    {
        this.button = button;
        this.game = game;
        this.gameView = gameView;
    }
    
    public void actionPerformed(ActionEvent e)
    {
        button.setText("$");
        game.reduceNumberStillHidden();
        gameView.updateUI();
    }
}