Help with error/code

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.awt.Color;
/**
 * Write a description of class Terrorist here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Enemy extends Actor
{
    private int i;

    public int time;
     
    MyWorld world =(MyWorld)getWorld();
    //HealthBar health = world.getHealthBar();
    /**
     * Act - do whatever the Terrorist wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public Enemy()
    {
    }
    public void act() 
    {
      Moving();  
      Damage();  
      time--;
      if(time <= 0)
      {
        setImage("Terrorist.png");
        }

    }  
    
    
    
    
    
    public void Moving()
    {
        
        if(getY() == 400) 
        {
            while (i < 30)
            {
                setLocation(getX()-1, getY());
                i++;
            }
        }
    
    }
    
    public void Damage()
    {
         int number = getWorld().numberOfObjects();   
         MyWorld world =(MyWorld)getWorld();
         HealthBar1 healthbar = world.getHealthBar1();
         HealthBar2 healthbar2 = world.getHealthBar2();
         HealthBar3 healthbar3 = world.getHealthBar3();
        if(Greenfoot.getRandomNumber(20000) < number)
        {
            getWorld().addObject(new Damage(), 500, 250); 
            world.addLife(-1);
            setImage("ShootingT.png");
            time = 50;
            Greenfoot.playSound("MP5_SMG-GunGuru-703432894.wav");
        } 
        if(number >= 1)
        {
            if(healthbar.Health <= 0)
                if(getX() < 400 && getX() > 200)
                    world.removeObject(this);
        }
        if(number >= 1)
        {
            if(healthbar2.Health <= 0)
            {
                if(getX() < 500 && getX() > 400)
                    world.removeObject(this);
            } 
        }
        if(number >= 1)
        {
            if(healthbar3.Health <= 0)
            {
                if(getX() < 700 && getX() > 500)
                    world.removeObject(this);
                }
        }
    }
}