Calling a mouse listener from an external class

Question

I have two classes one of them is where my JFrame is built and the second one is my Main_Loop and MouseListener.

How could I call the mouse listener to execute?

FIRST CLASS:

public class Main_Frame extends Main_Loop{

public static void main(String[]args){
    //SETTING UP THE JFRAME
    JFrame frame = new JFrame();
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(700,500);

    JPanel panel = new JPanel();
    panel.setLayout(null);

    frame.add(panel);

    Main_Loop cl = new Main_Loop();

    while (true){
    System.out.println(cl.clicked);
    }

SECOND CLASS:

public class Main_Loop implements MouseListener {

public int mouseY,x;
public int mouseX;
public boolean clicked;

public void mouseClicked(MouseEvent arg0) {
    mouseY = arg0.getX();
    mouseX = arg0.getY();
    clicked = true;
}

public void mouseEntered(MouseEvent arg0) {
}

public void mouseExited(MouseEvent arg0) {
}

public void mousePressed(MouseEvent arg0) {
}

public void mouseReleased(MouseEvent arg0) {
}
}