how to access the object of one frame on clicking a button without using this keyword

import java.awt.*; import java.awt.event.*;

class Mybuttons1 extends Frame {

public static void main(String args[])
{
    Button b1;


    Mybuttons mb=new Mybuttons();
    mb.setSize(400,400);
    mb.setTitle("My buttons");
    mb.setVisible(true);


    mb.setLayout(new FlowLayout());

    b1=new Button("Yellow");


    mb.add(b1);
    mb.add(b2);
    mb.add(b3);

    b1.addActionListener(new Myclass());


    mb.addWindowListener(new WindowAdapter()
    {
        public void windowClosing(WindowEvent e)
        {
            System.exit(0);
        }
    });

}

}

class Myclass extends Frame implements ActionListener { public void actionPerformed(ActionEvent ae) { String str=ae.getActionCommand();

    if(str.equals("Yellow"))
        this.setBackground(Color.yellow);

}

}