Making an HP bar

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.awt.Color;
/**
 * Write a description of class bg1 here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class bg1 extends World
{
    /**
     * Constructor for objects of class bg1.
     * 
     */
     public Bar bar = new Bar("Pikachu", "Health Points", 100,100);  
     public Bar2 bar2 = new Bar2("Charmander", "Health Points", 100, 100);
     
    public bg1()
    {    
        // Create a new world with 600x400 cells with a cell size of 1x1 pixels.
        super(600, 400, 1); 
        addObject(bar, 250,40);
        addObject(bar, 400, 40);

        prepare();
    }
    /**
     * Prepare the world for the start of the program. That is: create the initial
     * objects and add them to the world.
     */
    private void prepare()
    {
        Ground ground = new Ground();
        addObject(ground, 293, 393);
        Platform platform = new Platform();
        addObject(platform, 291, 193);
        Platform platform2 = new Platform();
        addObject(platform2, 107, 290);
        Platform platform3 = new Platform();
        addObject(platform3, 495, 283);
        Pikachu pikachu = new Pikachu();
        addObject(pikachu, 303, 105);
        Pikachu pikachu2 = new Pikachu();
        addObject(pikachu2, 295, 123);
        pikachu2.setLocation(179, 143);
        removeObject(pikachu2);
        pikachu.setLocation(88, 210);
        Charmander charmander = new Charmander();
        addObject(charmander, 517, 198);
        
    }
    GreenfootSound music = new GreenfootSound("19 Hyrule Field Main Theme.mp3");  
    public void started()  
    {  
        music.playLoop();  
    }  
    public void act()
    {
        if (bar.getValue() == 0)
        {
            showGameOverCharWins();
            Greenfoot.stop();
            return;
        }
        if (bar.getValue() == 0)
        {
            showGameoverPikaWins();
            Greenfoot.stop();
            return;
        }
    private void showGameOverCharWins()
    {
        addObject(new GameOverCharWins(), getWidth() / 2, getHeight() / 2);
    }
    private void showGameOverPikaWins()
    {
        addObject(new GameOverPikaWins(), getWidth() / 2, getHeight () / 2);
    }
    public void stopped()  
     {  
        music.stop();  
    } 
}
}