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

class StopGo{

  static window w;
 
  public static void main(String[] args){

    w = new window();
    w.addWindowListener(new myWindowListener());
    w.show();

  } 
}

 class myWindowListener extends WindowAdapter{
 
    public void windowClosing(WindowEvent e){System.exit(0);}
 
  }

class window extends Frame implements ActionListener{

  Label l;
  Button b;
  boolean state = true;

  // Constructor
  public window(){
    setLayout(new GridLayout(2,1));

    l = new Label();
    b = new Button();
    
    l.setBackground(Color.red);
    add(l);
    
    b.setLabel("Stop");
    b.setFont(new Font("Serif",Font.ITALIC,24));
    b.setBackground(Color.white);
    add(b);

    b.addActionListener(this);
    
    setSize(200,200);
  }
  
  public void actionPerformed(ActionEvent e){
    if(e.getSource()==b){
      switchState();
    }
  }

  public void switchState(){
    if(state){
      b.setLabel("Go");
      l.setBackground(Color.green);
    }
    else{
      b.setLabel("Stop");
      l.setBackground(Color.red);
    }
   
    state = !state;
    return;
  }
  
}