New to Java

So i have a menuing system. I create each window in a new class, but the problem is to detect which button is pressed in one of the provider classes by the driver class. I want the driver class to detect i have pressed for instance "list" to run the list class. Here i thought parameterized constructors would work best to get the variables across, but for some reason it is not working. Here is the code: (The gui works and detects the button is pushed etc.)

Provider class:

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


public class MainMenu implements ActionListener
{
	public String choice = "";
	
	public MainMenu(String c)
	{
		choice = c;
	}
	
	JFrame jf = new JFrame("Main Menu");
	
	Toolkit tk = Toolkit.getDefaultToolkit ();
 	
    int x = (int) tk.getScreenSize ().getWidth ();
    int y = (int) tk.getScreenSize ().getHeight ();
    
    ImageIcon ev = new ImageIcon("event.png");
    ImageIcon lb = new ImageIcon("list.png");
    ImageIcon cv = new ImageIcon("vote.png");
    ImageIcon bb = new ImageIcon("bio.png");
    
    Font f1 = new Font ("Tahoma", Font.BOLD, 25);
    Font f2 = new Font ("Chiller", Font.BOLD, 100);
    
    JLabel lbl = new JLabel("MAIN MENU");
    JLabel space = new JLabel ("");
    
	JButton jb1 = new JButton("Events", ev);
	JButton jb2 = new JButton("Leader Board", lb);
	JButton jb3 = new JButton("Cast Vote", cv);
	JButton jb4 = new JButton("Band Biographies", bb);
	
	GridLayout grid = new GridLayout(10,10,1,1);
	
	JPanel jp0 = new JPanel();
	JPanel jp1 = new JPanel();
	JPanel jp2 = new JPanel();
	JPanel jp3 = new JPanel();
	JPanel jp4 = new JPanel();
	
	public MainMenu() 
	{
    	lbl.setFont(f2);
    	
    	jf.setBounds(0,0, x,y);
		jf.setVisible(true);
		jf.setResizable(false);
		jf.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
		
		jb1.addActionListener(this);
		jb2.addActionListener(this);
		jb3.addActionListener(this);
		jb4.addActionListener(this);
		
		jb1.setFont(f1);
		jb2.setFont(f1);
		jb3.setFont(f1);
		jb4.setFont(f1);
	
		jp0.add(lbl);
    	jp1.add(jb1);
    	jp2.add(jb2);
    	jp3.add(jb3);
    	jp4.add(jb4);
    	
    	jf.setLayout(grid);
    	
    	jf.add(space);
    	jf.add(space);
    	jf.add(jp0);
    	jf.add(space);
    	jf.add(jp1);
    	jf.add(jp2);
    	jf.add(jp3);
    	jf.add(jp4);
    	
    	jf.repaint();
    }
    
    
    public void actionPerformed (ActionEvent e)
    {
    	if (e.getSource () == jb1)
    	{
    		choice = "events";
    		System.out.println(choice);//Just to test whether the buttons work...
    	
    	}
    	else if (e.getSource () == jb2)
    	{
    		choice = "list";
    		System.out.println(choice);
    	
    	}
    	else if (e.getSource () == jb3)
    	{
    		choice = "vote";
    		System.out.println(choice);
    
    	}
    	else if (e.getSource () == jb4)
    	{
    		choice = "bio";
    		System.out.println(choice);
    	
    	}
    }
    
    public String getChoice()
    {
    	
    	return choice;
    }
    
    
    
    
}

and here is the driver class which doesnt read the change in the choice variable:

public class PAT 
{
    
    public static void main(String[] args) //implements ActionListener
	{
		String choice = "";
		
 		MainMenu mm = new MainMenu(choice);
 		
 		new MainMenu();

 		while (choice.equals(""))
 		{
 		if (choice.equals("list"))
 		{
 			System.out.println("Parameterized constructor works");
 		}
 		}
    }
}

Any help or advice would be greatly appreciated. Thanks in advance.